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 (
    18516, 51007, 51004, 51005, 51010, 51008, 
    51012, 51013, 51011, 51015, 51006, 
    51021, 51016, 51024, 51017, 51019, 
    51018, 51022, 51014, 51045, 51422, 
    51025, 51440, 51029, 51424, 51429, 
    51442, 51060, 51436, 51430, 51433, 
    51027
  )

Query time 0.00048

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "44.81"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "p",
          "access_type": "range",
          "possible_keys": [
            "PRIMARY",
            "idx_group_id"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "product_id"
          ],
          "key_length": "3",
          "rows_examined_per_scan": 32,
          "rows_produced_per_join": 32,
          "filtered": "100.00",
          "index_condition": "(`test_uchur_k`.`p`.`product_id` in (18516,51007,51004,51005,51010,51008,51012,51013,51011,51015,51006,51021,51016,51024,51017,51019,51018,51022,51014,51045,51422,51025,51440,51029,51424,51429,51442,51060,51436,51430,51433,51027))",
          "cost_info": {
            "read_cost": "19.21",
            "eval_cost": "3.20",
            "prefix_cost": "22.41",
            "data_read_per_join": "512"
          },
          "used_columns": [
            "product_id",
            "parent_product_id",
            "group_id"
          ]
        }
      },
      {
        "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": [
            "test_uchur_k.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 32,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "8.00",
            "eval_cost": "3.20",
            "prefix_cost": "33.61",
            "data_read_per_join": "3K"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      },
      {
        "table": {
          "table_name": "g",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "id"
          ],
          "key_length": "3",
          "ref": [
            "test_uchur_k.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 32,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "8.00",
            "eval_cost": "3.20",
            "prefix_cost": "44.81",
            "data_read_per_join": "12K"
          },
          "used_columns": [
            "id",
            "code"
          ]
        }
      }
    ]
  }
}