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 = 7170 
WHERE 
  cscart_products_categories.product_id IN (
    86915, 86916, 86917, 86918, 86919, 86974, 
    86975, 86976, 86977, 86978, 86979, 
    86980, 87035, 87036, 87037, 87038, 
    87039, 87040, 87041, 87093, 87094, 
    87095, 87096, 87097, 87098, 87099, 
    84638, 84639, 84636, 84637, 91014, 
    91026, 91038, 91051, 84506, 84507, 
    84572, 84573, 84661, 84662, 89057, 
    84504, 84505, 84570, 84571, 89059, 
    89060, 84634, 84635, 86179, 86181, 
    86202, 86204, 86503, 86505, 86779, 
    86781, 84310, 84311, 89204, 89205, 
    89217, 89218, 89230, 89231, 83052, 
    83054, 83601, 83603, 90888, 90890, 
    90967, 90969, 86904, 86929, 86965, 
    86990, 87026, 87051, 87086, 87109, 
    89061, 84502, 84503, 84568, 84569, 
    89063, 89064, 89058, 89206, 89207, 
    89210, 89211, 89219, 89220, 89223
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00295

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "89.98"
    },
    "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": 158,
            "rows_produced_per_join": 158,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "16.12",
              "eval_cost": "15.80",
              "prefix_cost": "31.92",
              "data_read_per_join": "2K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (86915,86916,86917,86918,86919,86974,86975,86976,86977,86978,86979,86980,87035,87036,87037,87038,87039,87040,87041,87093,87094,87095,87096,87097,87098,87099,84638,84639,84636,84637,91014,91026,91038,91051,84506,84507,84572,84573,84661,84662,89057,84504,84505,84570,84571,89059,89060,84634,84635,86179,86181,86202,86204,86503,86505,86779,86781,84310,84311,89204,89205,89217,89218,89230,89231,83052,83054,83601,83603,90888,90890,90967,90969,86904,86929,86965,86990,87026,87051,87086,87109,89061,84502,84503,84568,84569,89063,89064,89058,89206,89207,89210,89211,89219,89220,89223))"
          }
        },
        {
          "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": 7,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "39.50",
              "eval_cost": "0.79",
              "prefix_cost": "87.22",
              "data_read_per_join": "20K"
            },
            "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')))"
          }
        },
        {
          "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": 7,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "1.98",
              "eval_cost": "0.79",
              "prefix_cost": "89.98",
              "data_read_per_join": "126"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}