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 (
    708, 841, 228, 452, 447, 829, 831, 818, 
    774, 823, 833, 368
  )

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.0488662,
    "nested_loop": [
      {
        "table": {
          "table_name": "p",
          "access_type": "range",
          "possible_keys": ["PRIMARY", "idx_group_id"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "loops": 1,
          "rows": 12,
          "cost": 0.0138334,
          "filtered": 100,
          "attached_condition": "p.product_id in (708,841,228,452,447,829,831,818,774,823,833,368)"
        }
      },
      {
        "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": ["u428615623_ecartifygonje.p.group_id"],
          "loops": 12,
          "rows": 1,
          "cost": 0.02348032,
          "filtered": 100
        }
      },
      {
        "table": {
          "table_name": "g",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["id"],
          "ref": ["u428615623_ecartifygonje.p.group_id"],
          "loops": 12,
          "rows": 1,
          "cost": 0.01155248,
          "filtered": 100
        }
      }
    ]
  }
}