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 = 7346 
WHERE 
  cscart_products_categories.product_id IN (
    99431, 99432, 99433, 99434, 99435, 99436, 
    99437, 99529, 99530, 99531, 99532, 
    99533, 99534, 99535, 99536, 99537, 
    99538, 99539, 99540, 99541, 99542, 
    99543, 99544, 99545, 99546, 99547, 
    99548, 99549, 99550, 99551, 99552, 
    99553, 99554, 99555, 99556, 99557, 
    99574, 99575, 99576, 100161, 100162, 
    100163, 100164, 100165, 100166, 100167, 
    100168, 101637, 101638, 101669, 101670, 
    101672, 101673, 101674, 101675, 101676, 
    101677, 101688, 101689, 101690, 101691, 
    101692, 101693, 101696, 101697, 101698, 
    101699, 101700, 101701, 101702, 101703, 
    101704, 101705, 101706, 101707, 101708, 
    101709, 101710, 101711, 101712, 101713, 
    101714, 101715, 101716, 101717, 101718, 
    101719, 101720, 101721, 101722, 101723, 
    101724, 101725, 101726, 101727, 101728
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.01820

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "141.90"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "14.93"
      },
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "ALL",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "rows_examined_per_scan": 208,
            "rows_produced_per_join": 8,
            "filtered": "4.00",
            "cost_info": {
              "read_cost": "20.72",
              "eval_cost": "0.83",
              "prefix_cost": "21.55",
              "data_read_per_join": "21K"
            },
            "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": "cscart_products_categories",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY",
              "link_type",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "nuie_scalesta_net.cscart_categories.category_id"
            ],
            "rows_examined_per_scan": 117,
            "rows_produced_per_join": 14,
            "filtered": "1.53",
            "cost_info": {
              "read_cost": "2.33",
              "eval_cost": "1.49",
              "prefix_cost": "121.75",
              "data_read_per_join": "238"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (99431,99432,99433,99434,99435,99436,99437,99529,99530,99531,99532,99533,99534,99535,99536,99537,99538,99539,99540,99541,99542,99543,99544,99545,99546,99547,99548,99549,99550,99551,99552,99553,99554,99555,99556,99557,99574,99575,99576,100161,100162,100163,100164,100165,100166,100167,100168,101637,101638,101669,101670,101672,101673,101674,101675,101676,101677,101688,101689,101690,101691,101692,101693,101696,101697,101698,101699,101700,101701,101702,101703,101704,101705,101706,101707,101708,101709,101710,101711,101712,101713,101714,101715,101716,101717,101718,101719,101720,101721,101722,101723,101724,101725,101726,101727,101728))"
          }
        },
        {
          "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": 14,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "3.73",
              "eval_cost": "1.49",
              "prefix_cost": "126.97",
              "data_read_per_join": "238"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}