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 (
    11320, 11321, 11322, 11323, 11324, 11325, 
    11326, 11327, 11328, 11329, 11330, 
    11331, 11332, 11333, 11334, 11335, 
    11336, 11337, 11338, 11339, 11340, 
    11341, 11342, 11343, 11344, 11345, 
    11346, 11347, 11348, 11349, 11350, 
    11351, 11352, 11353, 11354, 11355, 
    11356, 11357, 11358, 11359, 11360, 
    11361, 11362, 11363, 11364, 11365, 
    11366, 11367, 11368, 11369, 11370, 
    11371, 11372, 11373, 11374, 11375, 
    11376, 11377, 11378, 11379, 11380, 
    11381, 11382, 11383, 11384, 11385, 
    11386, 11387, 11388, 11389, 11390, 
    11391, 11392, 11393, 11394, 11395, 
    11396, 11397, 11398, 11399, 11400, 
    11401, 11402, 11403, 11404, 11405, 
    11406, 11407, 11408, 11409
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00229

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "69.21"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "2.91"
      },
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "ALL",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "rows_examined_per_scan": 40,
            "rows_produced_per_join": 1,
            "filtered": "4.00",
            "cost_info": {
              "read_cost": "4.54",
              "eval_cost": "0.16",
              "prefix_cost": "4.70",
              "data_read_per_join": "6K"
            },
            "used_columns": [
              "category_id",
              "storefront_id",
              "usergroup_ids",
              "status"
            ],
            "attached_condition": "((`gaseus`.`cscart_categories`.`storefront_id` in (0,1)) and ((`gaseus`.`cscart_categories`.`usergroup_ids` = '') or (0 <> find_in_set(0,`gaseus`.`cscart_categories`.`usergroup_ids`)) or (0 <> find_in_set(1,`gaseus`.`cscart_categories`.`usergroup_ids`))) and (`gaseus`.`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": [
              "gaseus.cscart_categories.category_id"
            ],
            "rows_examined_per_scan": 110,
            "rows_produced_per_join": 2,
            "filtered": "1.65",
            "index_condition": "(`gaseus`.`cscart_products_categories`.`product_id` in (11320,11321,11322,11323,11324,11325,11326,11327,11328,11329,11330,11331,11332,11333,11334,11335,11336,11337,11338,11339,11340,11341,11342,11343,11344,11345,11346,11347,11348,11349,11350,11351,11352,11353,11354,11355,11356,11357,11358,11359,11360,11361,11362,11363,11364,11365,11366,11367,11368,11369,11370,11371,11372,11373,11374,11375,11376,11377,11378,11379,11380,11381,11382,11383,11384,11385,11386,11387,11388,11389,11390,11391,11392,11393,11394,11395,11396,11397,11398,11399,11400,11401,11402,11403,11404,11405,11406,11407,11408,11409))",
            "cost_info": {
              "read_cost": "44.00",
              "eval_cost": "0.29",
              "prefix_cost": "66.30",
              "data_read_per_join": "46"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ]
          }
        }
      ]
    }
  }
}