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 (
    10447, 10460, 10400, 10397, 10399, 10403, 
    10402, 10401, 10404, 10356, 10351, 
    10368, 10009, 10012, 10474, 10420, 
    10387, 10354, 10428, 10453, 10471, 
    10365, 10398, 10463, 10406, 10436, 
    10480, 10486, 10545, 10350, 10412, 
    10488, 10384, 10449, 10452, 10462, 
    10461, 10472, 10482, 10553, 10381, 
    10013, 10371, 10373, 10394, 10466, 
    10467, 10551, 10011, 10370, 10372, 
    10388, 10457, 10459, 10475, 10555, 
    10007, 10008, 10010, 10352, 10353, 
    10357, 10358, 10378, 10379, 10383, 
    10392, 10393, 10405, 10411, 10414, 
    10425, 10427, 10470, 10359, 10361, 
    10376, 10390, 10426, 10429
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00250

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "92.81"
    },
    "grouping_operation": {
      "using_filesort": false,
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_products_categories",
            "access_type": "range",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "pt",
            "used_key_parts": [
              "product_id"
            ],
            "key_length": "3",
            "rows_examined_per_scan": 91,
            "rows_produced_per_join": 91,
            "filtered": "100.00",
            "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_products_categories`.`product_id` in (10447,10460,10400,10397,10399,10403,10402,10401,10404,10356,10351,10368,10009,10012,10474,10420,10387,10354,10428,10453,10471,10365,10398,10463,10406,10436,10480,10486,10545,10350,10412,10488,10384,10449,10452,10462,10461,10472,10482,10553,10381,10013,10371,10373,10394,10466,10467,10551,10011,10370,10372,10388,10457,10459,10475,10555,10007,10008,10010,10352,10353,10357,10358,10378,10379,10383,10392,10393,10405,10411,10414,10425,10427,10470,10359,10361,10376,10390,10426,10429))",
            "cost_info": {
              "read_cost": "51.86",
              "eval_cost": "9.10",
              "prefix_cost": "60.96",
              "data_read_per_join": "1K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ]
          }
        },
        {
          "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": [
              "softwarepirmam_hewadelivard_cscart_4.cscart_products_categories.category_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 4,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "22.75",
              "eval_cost": "0.46",
              "prefix_cost": "92.81",
              "data_read_per_join": "14K"
            },
            "used_columns": [
              "category_id",
              "storefront_id",
              "usergroup_ids",
              "status"
            ],
            "attached_condition": "((`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`storefront_id` in (0,1)) and ((`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`usergroup_ids` = '') or (0 <> find_in_set(0,`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`usergroup_ids`)) or (0 <> find_in_set(1,`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`usergroup_ids`))) and (`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`status` in ('A','H')))"
          }
        }
      ]
    }
  }
}