SELECT 
  f.*, 
  d.description 
FROM 
  cscart_form_options as f 
  LEFT JOIN cscart_form_descriptions as d ON d.object_id = f.element_id 
  AND d.lang_code = 'en' 
WHERE 
  f.page_id = 420 
  AND f.status = 'A' 
ORDER BY 
  f.position

Query time 0.00145

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.60"
    },
    "ordering_operation": {
      "using_filesort": true,
      "nested_loop": [
        {
          "table": {
            "table_name": "f",
            "access_type": "ref",
            "possible_keys": [
              "page_id"
            ],
            "key": "page_id",
            "used_key_parts": [
              "page_id",
              "status"
            ],
            "key_length": "6",
            "ref": [
              "const",
              "const"
            ],
            "rows_examined_per_scan": 9,
            "rows_produced_per_join": 9,
            "filtered": "100.00",
            "index_condition": "((`webmarco`.`f`.`page_id` <=> 420) and (`webmarco`.`f`.`status` <=> 'A'))",
            "cost_info": {
              "read_cost": "9.00",
              "eval_cost": "1.80",
              "prefix_cost": "10.80",
              "data_read_per_join": "6K"
            },
            "used_columns": [
              "element_id",
              "page_id",
              "parent_id",
              "element_type",
              "value",
              "position",
              "required",
              "status"
            ]
          }
        },
        {
          "table": {
            "table_name": "d",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "object_id",
              "lang_code"
            ],
            "key_length": "9",
            "ref": [
              "webmarco.f.element_id",
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 9,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "9.00",
              "eval_cost": "1.80",
              "prefix_cost": "21.60",
              "data_read_per_join": "216"
            },
            "used_columns": [
              "object_id",
              "description",
              "lang_code"
            ]
          }
        }
      ]
    }
  }
}