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 (
    40437, 40451, 2320, 2319, 48846, 40445, 
    40442, 47024, 41293, 40446, 47020, 
    47023, 47022, 40443, 40449, 40448, 
    40447, 49811, 40444, 41292, 40436, 
    47012, 40450, 41291, 41294, 40435, 
    47014, 40438, 47015, 40441
  )

Query time 0.00360

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": 30,
          "filtered": 100,
          "index_condition": "p.product_id in (40437,40451,2320,2319,48846,40445,40442,47024,41293,40446,47020,47023,47022,40443,40449,40448,40447,49811,40444,41292,40436,47012,40450,41291,41294,40435,47014,40438,47015,40441)"
        }
      },
      {
        "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
        }
      }
    ]
  }
}