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 (
    95, 96, 97, 100, 101, 102, 103, 104, 105, 
    106, 107, 108, 109, 110, 111, 112, 113, 
    114, 115, 116, 117, 118, 119, 120, 121, 
    122, 123, 124, 125, 126, 127, 128, 129, 
    130, 131, 132, 133, 134, 135, 136, 137, 
    138, 139, 140, 141, 142, 143, 144
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00102

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "42.20"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "1.60"
      },
      "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": "13.61",
            "index_condition": "(`danishecarter_latest`.`cscart_products_categories`.`product_id` in (95,96,97,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144))",
            "cost_info": {
              "read_cost": "14.97",
              "eval_cost": "0.32",
              "prefix_cost": "40.60",
              "data_read_per_join": "25"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ]
          }
        }
      ]
    }
  }
}

Result

product_id category_ids
95 248M
96 248M
97 242M
100 242M
101 238M
102 227M
103 242M
104 242M
105 238M
106 238M
107 227M
108 242M
109 227M
110 243M
111 243M
112 243M
113 237M
114 243M
115 208M
116 243M
117 237M
118 244M
119 244M
120 237M
121 244M
122 208M
123 244M
124 208M
125 237M
126 251M
127 209M
128 251M
129 209M
130 251M
131 209M
132 182M,179
133 179M,182
134 179,182M
135 179,182M
136 249M
137 249M
138 249M
139 249M
140 180M
141 180M
142 180M
143 180M
144 180M