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 (
    12, 162, 159, 158, 240, 241, 238, 239, 
    245, 242, 243, 214, 217, 218, 206, 207, 
    198, 199, 136, 65, 64, 63, 66, 62, 134, 
    135, 205, 129, 127, 131, 121, 103, 33, 
    32, 182, 246, 208, 229, 211, 210, 209, 
    71, 70, 69, 68, 67, 215, 226
  )

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "g",
      "access_type": "system",
      "possible_keys": ["PRIMARY"],
      "rows": 1,
      "filtered": 100
    },
    "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": ["const"],
      "rows": 2,
      "filtered": 100
    },
    "block-nl-join": {
      "table": {
        "table_name": "p",
        "access_type": "ALL",
        "possible_keys": ["PRIMARY", "idx_group_id"],
        "rows": 7,
        "filtered": 100,
        "attached_condition": "p.group_id = 10 and p.product_id in (12,162,159,158,240,241,238,239,245,242,243,214,217,218,206,207,198,199,136,65,64,63,66,62,134,135,205,129,127,131,121,103,33,32,182,246,208,229,211,210,209,71,70,69,68,67,215,226)"
      },
      "buffer_type": "flat",
      "buffer_size": "1Kb",
      "join_type": "BNL"
    }
  }
}