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 = 372 
WHERE 
  cscart_products_categories.product_id IN (
    5593, 5872, 5488, 2885, 5007, 5403, 8717, 
    5019, 5492, 2783, 5234, 5109, 5243, 
    5231, 5453, 5010, 5018, 5802, 6383, 
    6407, 7580, 5491, 5971, 2439
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00176

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "70.59"
    },
    "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": 79,
            "rows_produced_per_join": 79,
            "filtered": "100.00",
            "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_products_categories`.`product_id` in (5593,5872,5488,2885,5007,5403,8717,5019,5492,2783,5234,5109,5243,5231,5453,5010,5018,5802,6383,6407,7580,5491,5971,2439))",
            "cost_info": {
              "read_cost": "33.66",
              "eval_cost": "7.90",
              "prefix_cost": "41.56",
              "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": 3,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "19.75",
              "eval_cost": "0.40",
              "prefix_cost": "69.21",
              "data_read_per_join": "12K"
            },
            "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')))"
          }
        },
        {
          "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",
              "softwarepirmam_hewadelivard_cscart_4.cscart_products_categories.product_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 3,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "0.99",
              "eval_cost": "0.40",
              "prefix_cost": "70.59",
              "data_read_per_join": "63"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}

Result

product_id category_ids position
2439 454,453,166,372,174,190M 0
2783 372,461,464M 0
2885 372,384,459M 0
5007 561,555,557,552,553,372,250,563M 0
5010 561,555,557,552,553,372,250,563M 0
5018 561,555,557,552,553,372,250,563M 0
5019 561,555,557,552,553,372,250,563M 0
5109 250,372,560,553,552,555,557,562M 0
5231 372,550M 0
5234 372,551M 0
5243 372,549M 0
5403 372,466,467M 0
5453 466,372,574M 0
5488 466,372,575M 0
5491 466,372,575M 0
5492 466,372,575M 0
5593 466,372,573M 0
5802 372,583M 0
5872 572,372,582M 0
5971 454,190M
6383 372,583M 0
6407 566,372,595M 0
7580 461M
8717 372,454,453,166,174,190M 0