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 (
    26873, 829, 29729, 44488, 48122, 36764, 
    35487, 27862, 29730, 38626, 29731, 
    29733, 45570, 44768, 48065, 44489, 
    48695, 48676, 28439, 44490, 48715, 
    45575, 48043, 46584, 47565, 48064, 
    47621, 44491, 47220, 49020, 48678, 
    47973
  )

Query time 0.00904

JSON explain

{
  "query_block": {
    "select_id": 1,
    "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"],
          "rows": 33,
          "filtered": 100,
          "index_condition": "p.product_id in (26873,829,29729,44488,48122,36764,35487,27862,29730,38626,29731,29733,45570,44768,48065,44489,48695,48676,28439,44490,48715,45575,48043,46584,47565,48064,47621,44491,47220,49020,48678,47973)"
        }
      },
      {
        "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": ["dev_db.p.group_id"],
          "rows": 1,
          "filtered": 100
        }
      },
      {
        "table": {
          "table_name": "g",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["id"],
          "ref": ["dev_db.p.group_id"],
          "rows": 1,
          "filtered": 100
        }
      }
    ]
  }
}