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 
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') 
WHERE 
  cscart_products_categories.product_id IN (
    206, 207, 208, 209, 210, 211, 212, 213, 
    215, 217, 218, 220, 222, 224, 225, 226, 
    227, 228, 229, 230, 231, 232, 233, 234, 
    235, 236, 237, 238, 239, 242, 243, 78, 
    79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 
    89, 90, 91, 92, 93, 94
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00100

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "42.11"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "1.51"
      },
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "ALL",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "rows_examined_per_scan": 98,
            "rows_produced_per_join": 3,
            "filtered": "4.00",
            "cost_info": {
              "read_cost": "22.49",
              "eval_cost": "0.78",
              "prefix_cost": "23.28",
              "data_read_per_join": "13K"
            },
            "used_columns": [
              "category_id",
              "storefront_id",
              "usergroup_ids",
              "status"
            ],
            "attached_condition": "((`danishecarter_latest`.`cscart_categories`.`storefront_id` in (0,1)) and ((`danishecarter_latest`.`cscart_categories`.`usergroup_ids` = '') or find_in_set(0,`danishecarter_latest`.`cscart_categories`.`usergroup_ids`) or find_in_set(1,`danishecarter_latest`.`cscart_categories`.`usergroup_ids`)) and (`danishecarter_latest`.`cscart_categories`.`status` in ('A','H')))"
          }
        },
        {
          "table": {
            "table_name": "cscart_products_categories",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "danishecarter_latest.cscart_categories.category_id"
            ],
            "rows_examined_per_scan": 3,
            "rows_produced_per_join": 1,
            "filtered": "12.83",
            "index_condition": "(`danishecarter_latest`.`cscart_products_categories`.`product_id` in (206,207,208,209,210,211,212,213,215,217,218,220,222,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,242,243,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94))",
            "cost_info": {
              "read_cost": "14.97",
              "eval_cost": "0.30",
              "prefix_cost": "40.60",
              "data_read_per_join": "24"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ]
          }
        }
      ]
    }
  }
}

Result

product_id category_ids
78 226M
79 226M
80 226M
81 226M
82 246M
83 246M
84 246M
85 246M
86 238M
87 246M
88 247M
89 247M
90 247M
91 227M
92 227M
93 248M
94 248M
206 171M
207 171M
208 171M
209 172M
210 172M
211 172M
212 172M
213 201M
215 201M
217 168M
218 168M
220 169M
222 169M
224 165M
225 165M
226 201M
227 170M
228 170M
229 170M
230 216M
231 216M
232 216M
233 217M
234 217M
235 217M
236 218M
237 218M
238 235M
239 235M
242 178M
243 178M