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 (
    208, 209, 210, 211, 212, 213, 215, 217, 
    218, 220, 222, 224, 225, 226, 227, 228, 
    229, 230, 231, 232, 233, 234, 235, 236, 
    237, 238, 239, 242, 243, 78, 79, 80
  )

Query time 0.00068

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.024554205,
    "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": 1,
          "cost": 0.006792605,
          "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": ["lvshop.g.id"],
          "loops": 1,
          "rows": 2,
          "cost": 0.004452,
          "filtered": 75
        }
      },
      {
        "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": ["lvshop.g.id"],
          "loops": 1.5,
          "rows": 7,
          "cost": 0.0133096,
          "filtered": 100,
          "index_condition": "p.product_id in (208,209,210,211,212,213,215,217,218,220,222,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,242,243,78,79,80)"
        }
      }
    ]
  }
}