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 (
    59, 58, 60, 56, 57, 30, 53, 52, 33, 32, 55, 
    29, 50, 51, 49, 48, 54, 65, 64, 63, 62, 
    66
  )

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.05491401,
    "nested_loop": [
      {
        "table": {
          "table_name": "g",
          "access_type": "index",
          "possible_keys": ["PRIMARY"],
          "key": "idx_group_code",
          "key_length": "387",
          "used_key_parts": ["code"],
          "loops": 1,
          "rows": 2,
          "cost": 0.00693929,
          "filtered": 100,
          "using_index": true
        }
      },
      {
        "table": {
          "table_name": "f",
          "access_type": "ref",
          "possible_keys": ["idx_group_id"],
          "key": "idx_group_id",
          "key_length": "3",
          "used_key_parts": ["group_id"],
          "ref": ["u985510652_ecartify_abhi.g.id"],
          "loops": 2,
          "rows": 2,
          "cost": 0.0072656,
          "filtered": 100
        }
      },
      {
        "table": {
          "table_name": "p",
          "access_type": "ref",
          "possible_keys": ["PRIMARY", "idx_group_id"],
          "key": "idx_group_id",
          "key_length": "3",
          "used_key_parts": ["group_id"],
          "ref": ["u985510652_ecartify_abhi.g.id"],
          "loops": 4,
          "rows": 9,
          "cost": 0.04070912,
          "filtered": 56.41025543,
          "index_condition": "p.product_id in (59,58,60,56,57,30,53,52,33,32,55,29,50,51,49,48,54,65,64,63,62,66)"
        }
      }
    ]
  }
}