SELECT 
  f.feature_id, 
  f.purpose, 
  p.product_id, 
  p.parent_product_id, 
  g.id, 
  g.code 
FROM 
  cscart_product_variation_group_features AS f 
  INNER JOIN cscart_product_variation_groups AS g ON f.group_id = g.id 
  INNER JOIN cscart_product_variation_group_products AS p ON f.group_id = p.group_id 
WHERE 
  p.product_id IN (
    114, 108, 104, 121, 103, 112, 97, 116, 
    111, 287, 315, 110, 118, 286, 123, 119, 
    100, 289
  )

Query time 0.00051

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "88.46"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "p",
          "access_type": "ALL",
          "possible_keys": [
            "PRIMARY",
            "idx_group_id"
          ],
          "rows_examined_per_scan": 61,
          "rows_produced_per_join": 18,
          "filtered": "29.51",
          "cost_info": {
            "read_cost": "10.79",
            "eval_cost": "3.60",
            "prefix_cost": "14.39",
            "data_read_per_join": "288"
          },
          "used_columns": [
            "product_id",
            "parent_product_id",
            "group_id"
          ],
          "attached_condition": "(`pankajecarter_systemfour`.`p`.`product_id` in (114,108,104,121,103,112,97,116,111,287,315,110,118,286,123,119,100,289))"
        }
      },
      {
        "table": {
          "table_name": "g",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "id"
          ],
          "key_length": "3",
          "ref": [
            "pankajecarter_systemfour.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 18,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "18.00",
            "eval_cost": "3.60",
            "prefix_cost": "35.99",
            "data_read_per_join": "7K"
          },
          "used_columns": [
            "id",
            "code"
          ]
        }
      },
      {
        "table": {
          "table_name": "f",
          "access_type": "ref",
          "possible_keys": [
            "idx_group_id"
          ],
          "key": "idx_group_id",
          "used_key_parts": [
            "group_id"
          ],
          "key_length": "3",
          "ref": [
            "pankajecarter_systemfour.p.group_id"
          ],
          "rows_examined_per_scan": 3,
          "rows_produced_per_join": 64,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "39.60",
            "eval_cost": "12.87",
            "prefix_cost": "88.46",
            "data_read_per_join": "6K"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      }
    ]
  }
}