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 = 7257 
WHERE 
  cscart_products_categories.product_id IN (
    87960, 88030, 88086, 88019, 87992, 88001, 
    88005, 87939, 87989, 87943, 87973, 
    87999, 90808, 87965, 88014, 88020, 
    92893, 92894, 93002, 93003, 93004, 
    93005, 93006, 93007
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00154

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "57.88"
    },
    "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": 64,
            "rows_produced_per_join": 64,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "6.68",
              "eval_cost": "6.40",
              "prefix_cost": "13.08",
              "data_read_per_join": "1024"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (87960,88030,88086,88019,87992,88001,88005,87939,87989,87943,87973,87999,90808,87965,88014,88020,92893,92894,93002,93003,93004,93005,93006,93007))"
          }
        },
        {
          "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": 64,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "16.00",
              "eval_cost": "6.40",
              "prefix_cost": "35.48",
              "data_read_per_join": "1024"
            },
            "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": 3,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "16.00",
              "eval_cost": "0.32",
              "prefix_cost": "57.88",
              "data_read_per_join": "8K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}

Result

product_id category_ids position
87939 7349,7261M
87943 7349,7261M
87960 7349,7261M
87965 7349,7261M
87973 7349,7261M
87989 7349,7261M
87992 7349,7261M
87999 7349,7261M
88001 7349,7261M
88005 7349,7261M
88014 7349,7261M
88019 7349,7261M
88020 7349,7261M
88030 7349,7261M
88086 7262,7256M
90808 7349,7261M
92893 7241,7309,7346,7208M
92894 7241,7309,7346,7208M
93002 7241,7309,7346,7208M
93003 7241,7309,7346,7208M
93004 7241,7309,7346,7208M
93005 7241,7309,7346,7208M
93006 7241,7309,7346,7208M
93007 7241,7309,7346,7208M