SELECT 
  cscart_multi_decproducts_categories.product_id, 
  GROUP_CONCAT(
    IF(
      cscart_multi_decproducts_categories.link_type = "M", 
      CONCAT(
        cscart_multi_decproducts_categories.category_id, 
        "M"
      ), 
      cscart_multi_decproducts_categories.category_id
    )
  ) AS category_ids 
FROM 
  cscart_multi_decproducts_categories 
  INNER JOIN cscart_multi_deccategories ON cscart_multi_deccategories.category_id = cscart_multi_decproducts_categories.category_id 
  AND cscart_multi_deccategories.storefront_id IN (0, 1) 
  AND (
    cscart_multi_deccategories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_multi_deccategories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_multi_deccategories.usergroup_ids
    )
  ) 
  AND cscart_multi_deccategories.status IN ('A', 'H') 
WHERE 
  cscart_multi_decproducts_categories.product_id IN (
    133, 132, 125, 120, 223, 225, 224, 146, 
    147, 93, 117, 219, 222, 220, 221, 87, 
    113, 139, 118, 83, 157, 123, 174, 171
  ) 
GROUP BY 
  cscart_multi_decproducts_categories.product_id

Query time 0.00085

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "31.28"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "0.65"
      },
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_multi_deccategories",
            "access_type": "ALL",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "rows_examined_per_scan": 84,
            "rows_produced_per_join": 3,
            "filtered": "4.00",
            "cost_info": {
              "read_cost": "19.61",
              "eval_cost": "0.67",
              "prefix_cost": "20.28",
              "data_read_per_join": "8K"
            },
            "used_columns": [
              "category_id",
              "storefront_id",
              "usergroup_ids",
              "status"
            ],
            "attached_condition": "((`vishalecarter_multi_dec`.`cscart_multi_deccategories`.`storefront_id` in (0,1)) and ((`vishalecarter_multi_dec`.`cscart_multi_deccategories`.`usergroup_ids` = '') or find_in_set(0,`vishalecarter_multi_dec`.`cscart_multi_deccategories`.`usergroup_ids`) or find_in_set(1,`vishalecarter_multi_dec`.`cscart_multi_deccategories`.`usergroup_ids`)) and (`vishalecarter_multi_dec`.`cscart_multi_deccategories`.`status` in ('A','H')))"
          }
        },
        {
          "table": {
            "table_name": "cscart_multi_decproducts_categories",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "vishalecarter_multi_dec.cscart_multi_deccategories.category_id"
            ],
            "rows_examined_per_scan": 2,
            "rows_produced_per_join": 0,
            "filtered": "9.70",
            "index_condition": "(`vishalecarter_multi_dec`.`cscart_multi_decproducts_categories`.`product_id` in (133,132,125,120,223,225,224,146,147,93,117,219,222,220,221,87,113,139,118,83,157,123,174,171))",
            "cost_info": {
              "read_cost": "9.00",
              "eval_cost": "0.13",
              "prefix_cost": "30.63",
              "data_read_per_join": "10"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ]
          }
        }
      ]
    }
  }
}

Result

product_id category_ids
83 246M
87 246M
93 248M
113 237M
117 237M
118 244M
120 237M
123 244M
125 237M
132 179,182M
133 182,179M
139 249M
146 179M
147 179M
157 181M
171 252M
174 252M
219 169M
220 169M
221 169M
222 169M
223 165M
224 165M
225 165M