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 (
    10975, 5759, 1925, 11317, 10974, 11013, 
    11023, 11027, 11315, 11314, 11313, 
    11312, 11036, 11073, 11089, 11309, 
    11302, 10884, 11300, 11256, 11257, 
    11316, 10830, 11286, 11285, 11284, 
    11283, 3875, 11282, 10638, 10870, 11031, 
    11030, 10738, 11253, 11025, 11267, 
    11266, 11265, 11264, 11263, 11262, 
    11259, 11261, 10848, 10979, 11012, 
    11024, 11090, 11234, 11235, 11258, 
    11254, 11269, 10333, 11015, 11018, 
    11019, 11238, 11251, 11307, 11308, 
    11002, 10335
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00781

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "861.87"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "12.62"
      },
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "ALL",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "rows_examined_per_scan": 125,
            "rows_produced_per_join": 5,
            "filtered": "4.00",
            "cost_info": {
              "read_cost": "28.14",
              "eval_cost": "1.00",
              "prefix_cost": "29.14",
              "data_read_per_join": "13K"
            },
            "used_columns": [
              "category_id",
              "usergroup_ids",
              "status",
              "storefront_id"
            ],
            "attached_condition": "((`ea201_francemaqu`.`cscart_categories`.`storefront_id` in (0,1)) and ((`ea201_francemaqu`.`cscart_categories`.`usergroup_ids` = '') or find_in_set(0,`ea201_francemaqu`.`cscart_categories`.`usergroup_ids`) or find_in_set(1,`ea201_francemaqu`.`cscart_categories`.`usergroup_ids`)) and (`ea201_francemaqu`.`cscart_categories`.`status` in ('A','H')))"
          }
        },
        {
          "table": {
            "table_name": "cscart_products_categories",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "ea201_francemaqu.cscart_categories.category_id"
            ],
            "rows_examined_per_scan": 136,
            "rows_produced_per_join": 12,
            "filtered": "1.86",
            "index_condition": "(`ea201_francemaqu`.`cscart_products_categories`.`product_id` in (10975,5759,1925,11317,10974,11013,11023,11027,11315,11314,11313,11312,11036,11073,11089,11309,11302,10884,11300,11256,11257,11316,10830,11286,11285,11284,11283,3875,11282,10638,10870,11031,11030,10738,11253,11025,11267,11266,11265,11264,11263,11262,11259,11261,10848,10979,11012,11024,11090,11234,11235,11258,11254,11269,10333,11015,11018,11019,11238,11251,11307,11308,11002,10335))",
            "cost_info": {
              "read_cost": "684.10",
              "eval_cost": "2.52",
              "prefix_cost": "849.24",
              "data_read_per_join": "201"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ]
          }
        }
      ]
    }
  }
}