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 = 7195 
WHERE 
  cscart_products_categories.product_id IN (
    99291, 99292, 99293, 99294, 99295, 99296, 
    99297, 99298, 99299, 99300, 99301, 
    99302, 99303, 99304, 99305, 99306, 
    99307, 99308, 99309, 99310, 99311, 
    99312, 99319, 99320, 99321, 99356, 
    99357, 99358, 99359, 99360
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00143

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "28.17"
    },
    "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": 31,
            "rows_produced_per_join": 31,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "3.37",
              "eval_cost": "3.10",
              "prefix_cost": "6.47",
              "data_read_per_join": "496"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (99291,99292,99293,99294,99295,99296,99297,99298,99299,99300,99301,99302,99303,99304,99305,99306,99307,99308,99309,99310,99311,99312,99319,99320,99321,99356,99357,99358,99359,99360))"
          }
        },
        {
          "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": 31,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "7.75",
              "eval_cost": "3.10",
              "prefix_cost": "17.32",
              "data_read_per_join": "496"
            },
            "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": 1,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "7.75",
              "eval_cost": "0.16",
              "prefix_cost": "28.17",
              "data_read_per_join": "4K"
            },
            "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
99291 7254M
99292 7254M
99293 7254M
99294 7254M
99295 7254M
99296 7254M
99297 7254M
99298 7254M
99299 7254M
99300 7254M
99301 7254M
99302 7254M
99303 7254M
99304 7254M
99305 7254M
99306 7254M
99307 7254M
99308 7254M
99309 7254M
99310 7254M
99311 7254M
99312 7254M
99319 7331,7253M
99320 7252M
99321 7252M
99356 7222M
99357 7222M
99358 7222M
99359 7222M
99360 7222M