SELECT 
  cscart_profile_fields.*, 
  cscart_profile_field_descriptions.description, 
  cscart_profile_fields.checkout_required as required 
FROM 
  cscart_profile_fields 
  LEFT JOIN cscart_profile_field_descriptions ON cscart_profile_field_descriptions.object_id = cscart_profile_fields.field_id 
  AND cscart_profile_field_descriptions.object_type = 'F' 
  AND lang_code = 'en' 
WHERE 
  1 = 1 
  AND cscart_profile_fields.profile_type = 'U' 
  AND cscart_profile_fields.checkout_show = 'Y' 
  AND (
    cscart_profile_fields.usergroup_ids = 0
  ) 
ORDER BY 
  cscart_profile_fields.position

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "6.79"
    },
    "ordering_operation": {
      "using_filesort": true,
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_profile_fields",
            "access_type": "ref",
            "possible_keys": [
              "checkout_show"
            ],
            "key": "checkout_show",
            "used_key_parts": [
              "checkout_show"
            ],
            "key_length": "4",
            "ref": [
              "const"
            ],
            "rows_examined_per_scan": 17,
            "rows_produced_per_join": 0,
            "filtered": "1.92",
            "index_condition": "(`webmarco`.`cscart_profile_fields`.`checkout_show` <=> 'Y')",
            "cost_info": {
              "read_cost": "3.00",
              "eval_cost": "0.07",
              "prefix_cost": "6.40",
              "data_read_per_join": "596"
            },
            "used_columns": [
              "field_id",
              "field_name",
              "profile_show",
              "profile_required",
              "checkout_show",
              "checkout_required",
              "partner_show",
              "partner_required",
              "storefront_show",
              "field_type",
              "profile_type",
              "position",
              "is_default",
              "section",
              "matching_id",
              "class",
              "wrapper_class",
              "autocomplete_type",
              "ec_multiple",
              "usergroup_ids"
            ],
            "attached_condition": "((`webmarco`.`cscart_profile_fields`.`profile_type` = 'U') and (`webmarco`.`cscart_profile_fields`.`usergroup_ids` = 0))"
          }
        },
        {
          "table": {
            "table_name": "cscart_profile_field_descriptions",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "object_id",
              "object_type",
              "lang_code"
            ],
            "key_length": "12",
            "ref": [
              "webmarco.cscart_profile_fields.field_id",
              "const",
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 0,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "0.33",
              "eval_cost": "0.07",
              "prefix_cost": "6.79",
              "data_read_per_join": "256"
            },
            "used_columns": [
              "object_id",
              "description",
              "object_type",
              "lang_code"
            ]
          }
        }
      ]
    }
  }
}

Result

field_id field_name profile_show profile_required checkout_show checkout_required partner_show partner_required storefront_show field_type profile_type position is_default section matching_id class wrapper_class autocomplete_type ec_multiple usergroup_ids description required
27 s_country Y Y Y Y Y Y Y O U 1 Y S 26 shipping-country country N 0 Country Y
25 s_state Y Y Y Y Y Y Y A U 2 Y S 24 shipping-state state N 0 State / Region Y
23 s_city Y Y Y Y Y Y Y I U 3 Y S 22 shipping-city city N 0 City Y
6 firstname Y Y Y N Y Y Y I U 10 Y C 0 first-name given-name N 0 First name N
14 b_firstname Y N Y N Y N Y I U 10 Y B 15 billing-first-name given-name N 0 First name N
7 lastname Y Y Y N Y Y Y I U 20 Y C 0 last-name surname N 0 Last name N
16 b_lastname Y N Y N Y N Y I U 20 Y B 17 billing-last-name surname N 0 Last name N
18 b_address Y Y Y N Y Y Y I U 30 Y B 19 billing-address litecheckout__field--xlarge street-address N 0 Address N
19 s_address Y Y Y Y Y Y Y I U 30 Y S 18 shipping-address litecheckout__field--xlarge shipping street-address N 0 Address Y
9 phone Y N Y N Y Y Y P U 40 Y C 0 shipping-phone tel N 0 Phone N
24 b_state Y Y Y N Y Y Y A U 50 Y B 25 billing-state state N 0 State / Region N
32 email Y Y Y Y Y Y Y E U 50 Y C 0 litecheckout__field--full off N 0 E-mail Y
26 b_country Y Y Y N Y Y Y O U 60 Y B 27 billing-country country N 0 Country N
22 b_city Y N Y N Y Y Y I U 70 Y B 23 billing-city city N 0 City N
28 b_zipcode Y N Y N Y Y Y Z U 80 Y B 29 billing-zip-code litecheckout__field--xsmall postal-code N 0 Zip/postal code N
29 s_zipcode N N Y Y Y Y Y Z U 80 Y S 28 shipping-zip-code litecheckout__field--xsmall shipping postal-code N 0 Zip/postal code Y
30 b_phone Y N Y N Y N Y P U 90 Y B 31 billing-phone tel N 0 Phone N