SELECT 
  cscart_products_categories.product_id, 
  GROUP_CONCAT(
    IF(
      cscart_products_categories.link_type = "M", 
      CONCAT(
        cscart_products_categories.category_id, 
        "M"
      ), 
      cscart_products_categories.category_id
    )
  ) AS category_ids 
FROM 
  cscart_products_categories 
  INNER JOIN cscart_categories ON cscart_categories.category_id = cscart_products_categories.category_id 
  AND cscart_categories.storefront_id IN (0, 1) 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
WHERE 
  cscart_products_categories.product_id IN (
    415304, 415296, 415297, 415303, 415291, 
    415290, 415228, 415289, 415308, 415240, 
    427824, 415310, 415305, 427787, 415219, 
    415294, 415302, 415311, 415299, 415242, 
    415300, 415224, 415238, 415217, 415312, 
    415211, 427780, 415241, 415298, 415307, 
    415288, 415232, 427775, 415293, 427786, 
    427782, 427823, 415295, 415306, 415235, 
    427781, 428031, 427738, 427829, 415309, 
    428033, 428032, 427821, 427777, 415292, 
    427779, 427778, 427788, 427826, 427789, 
    415213, 435511, 435512, 435513, 435515, 
    435514, 435516, 435517
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00194

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "146.74"
    },
    "grouping_operation": {
      "using_filesort": false,
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_products_categories",
            "access_type": "range",
            "possible_keys": [
              "PRIMARY",
              "link_type",
              "pt"
            ],
            "key": "pt",
            "used_key_parts": [
              "product_id"
            ],
            "key_length": "3",
            "rows_examined_per_scan": 91,
            "rows_produced_per_join": 91,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "19.34",
              "eval_cost": "18.20",
              "prefix_cost": "37.54",
              "data_read_per_join": "1K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`webmarco`.`cscart_products_categories`.`product_id` in (415304,415296,415297,415303,415291,415290,415228,415289,415308,415240,427824,415310,415305,427787,415219,415294,415302,415311,415299,415242,415300,415224,415238,415217,415312,415211,427780,415241,415298,415307,415288,415232,427775,415293,427786,427782,427823,415295,415306,415235,427781,428031,427738,427829,415309,428033,428032,427821,427777,415292,427779,427778,427788,427826,427789,415213,435511,435512,435513,435515,435514,435516,435517))"
          }
        },
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "webmarco.cscart_products_categories.category_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 4,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "91.00",
              "eval_cost": "0.91",
              "prefix_cost": "146.74",
              "data_read_per_join": "26K"
            },
            "used_columns": [
              "category_id",
              "usergroup_ids",
              "status",
              "storefront_id"
            ],
            "attached_condition": "((`webmarco`.`cscart_categories`.`storefront_id` in (0,1)) and ((`webmarco`.`cscart_categories`.`usergroup_ids` = '') or find_in_set(0,`webmarco`.`cscart_categories`.`usergroup_ids`) or find_in_set(1,`webmarco`.`cscart_categories`.`usergroup_ids`)) and (`webmarco`.`cscart_categories`.`status` in ('A','H')))"
          }
        }
      ]
    }
  }
}