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, 
  product_position_source.position AS position 
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') 
  LEFT JOIN cscart_products_categories AS product_position_source ON cscart_products_categories.product_id = product_position_source.product_id 
  AND product_position_source.category_id = 7165 
WHERE 
  cscart_products_categories.product_id IN (
    94215, 94216, 94217, 94218, 94219, 94220, 
    94221, 94222, 94223, 94224, 94225, 
    94226, 94227, 94228, 94229, 94230, 
    94231, 94232, 94233, 94234, 94235, 
    94236, 94237, 94238, 94239, 94240, 
    94241, 94242, 94243, 94244, 94245, 
    94246, 94247, 94248, 94249, 94250, 
    94251, 94252, 94253, 94254, 94255, 
    94256, 94257, 94258, 94259, 94260, 
    94261, 94262, 94263, 94264, 94265, 
    94266, 94267, 94268, 94269, 94270, 
    94271, 94272, 94273, 94274, 94275, 
    94276, 94277, 94278, 94279, 94280, 
    94281, 94282, 94283, 94284, 94285, 
    94286, 94287, 94288, 94289, 94290, 
    94291, 94292, 94293, 94294, 94295, 
    94296, 94297, 94298, 94299, 94300, 
    94301, 94302, 94303, 94304, 94305, 
    94306, 94307, 94308, 94309, 94310
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00653

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "86.69"
    },
    "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": 96,
            "rows_produced_per_join": 96,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "9.89",
              "eval_cost": "9.60",
              "prefix_cost": "19.49",
              "data_read_per_join": "1K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (94215,94216,94217,94218,94219,94220,94221,94222,94223,94224,94225,94226,94227,94228,94229,94230,94231,94232,94233,94234,94235,94236,94237,94238,94239,94240,94241,94242,94243,94244,94245,94246,94247,94248,94249,94250,94251,94252,94253,94254,94255,94256,94257,94258,94259,94260,94261,94262,94263,94264,94265,94266,94267,94268,94269,94270,94271,94272,94273,94274,94275,94276,94277,94278,94279,94280,94281,94282,94283,94284,94285,94286,94287,94288,94289,94290,94291,94292,94293,94294,94295,94296,94297,94298,94299,94300,94301,94302,94303,94304,94305,94306,94307,94308,94309,94310))"
          }
        },
        {
          "table": {
            "table_name": "product_position_source",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id",
              "product_id"
            ],
            "key_length": "6",
            "ref": [
              "const",
              "nuie_scalesta_net.cscart_products_categories.product_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 96,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "24.00",
              "eval_cost": "9.60",
              "prefix_cost": "53.09",
              "data_read_per_join": "1K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        },
        {
          "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": [
              "nuie_scalesta_net.cscart_products_categories.category_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 4,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "24.00",
              "eval_cost": "0.48",
              "prefix_cost": "86.69",
              "data_read_per_join": "12K"
            },
            "used_columns": [
              "category_id",
              "usergroup_ids",
              "status",
              "storefront_id"
            ],
            "attached_condition": "((`nuie_scalesta_net`.`cscart_categories`.`storefront_id` in (0,1)) and ((`nuie_scalesta_net`.`cscart_categories`.`usergroup_ids` = '') or (0 <> find_in_set(0,`nuie_scalesta_net`.`cscart_categories`.`usergroup_ids`)) or (0 <> find_in_set(1,`nuie_scalesta_net`.`cscart_categories`.`usergroup_ids`))) and (`nuie_scalesta_net`.`cscart_categories`.`status` in ('A','H')))"
          }
        }
      ]
    }
  }
}