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 = 7237 
WHERE 
  cscart_products_categories.product_id IN (
    94930, 94931, 94932, 94933, 94934, 94935, 
    94936, 94937, 94938, 94939, 94940, 
    94941, 94942, 94943, 94944, 94945, 
    94946, 94947, 94948, 94949, 95100, 
    95558, 95559, 95560, 95638, 95640, 
    95645, 95646, 95653, 95790, 95932, 
    95933, 95936, 95940, 96245, 96246, 
    96247, 96248, 96249, 96250, 96251, 
    96252, 96253, 96254, 96255, 96256, 
    96257, 96258, 96259, 96260, 96261, 
    96262, 96263, 96264, 96265, 96266, 
    96267, 96268, 96269, 96270, 96271, 
    96272, 96273, 96274, 96275, 96276, 
    96277, 96278, 96279, 96280, 96281, 
    96282, 96283, 96284, 96285, 96286, 
    96287, 96288, 96289, 96290, 96291, 
    96292, 96293, 96294, 96522, 96523, 
    96524, 96525, 96526, 96527, 96528, 
    96574, 96575, 96576, 96577, 96578
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.01628

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 (94930,94931,94932,94933,94934,94935,94936,94937,94938,94939,94940,94941,94942,94943,94944,94945,94946,94947,94948,94949,95100,95558,95559,95560,95638,95640,95645,95646,95653,95790,95932,95933,95936,95940,96245,96246,96247,96248,96249,96250,96251,96252,96253,96254,96255,96256,96257,96258,96259,96260,96261,96262,96263,96264,96265,96266,96267,96268,96269,96270,96271,96272,96273,96274,96275,96276,96277,96278,96279,96280,96281,96282,96283,96284,96285,96286,96287,96288,96289,96290,96291,96292,96293,96294,96522,96523,96524,96525,96526,96527,96528,96574,96575,96576,96577,96578))"
          }
        },
        {
          "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')))"
          }
        }
      ]
    }
  }
}