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 = 7148 
WHERE 
  cscart_products_categories.product_id IN (
    98845, 98846, 98847, 98848, 98849, 98850, 
    98851, 98852, 98853, 98854, 98855, 
    98856, 98857, 98858, 98874, 98875, 
    98876, 98877, 98897, 98914, 98915, 
    98916, 98917, 98918, 98919, 98920, 
    98921, 98922, 98923, 98924
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00130

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "25.81"
    },
    "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": 45,
            "rows_produced_per_join": 45,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "4.78",
              "eval_cost": "4.50",
              "prefix_cost": "9.28",
              "data_read_per_join": "720"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (98845,98846,98847,98848,98849,98850,98851,98852,98853,98854,98855,98856,98857,98858,98874,98875,98876,98877,98897,98914,98915,98916,98917,98918,98919,98920,98921,98922,98923,98924))"
          }
        },
        {
          "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": 2,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "11.25",
              "eval_cost": "0.23",
              "prefix_cost": "25.03",
              "data_read_per_join": "5K"
            },
            "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": 2,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "0.56",
              "eval_cost": "0.23",
              "prefix_cost": "25.81",
              "data_read_per_join": "36"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}

Result

product_id category_ids position
98845 7194M
98846 7194M
98847 7194M
98848 7194M
98849 7194M
98850 7194M
98851 7263M
98852 7263M
98853 7263M
98854 7263M
98855 7263M
98856 7263M
98857 7263M
98858 7263M
98874 7241,7309,7346,7208M
98875 7241,7309,7346,7208M
98876 7241,7309,7346,7208M
98877 7241,7309,7346,7208M
98897 7341,7342,7343,7157M
98914 7194M
98915 7194M
98916 7194M
98917 7194M
98918 7194M
98919 7194M
98920 7194M
98921 7194M
98922 7194M
98923 7194M
98924 7194M