SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd8b6ffb2cc98e65458b87f51a8ef8973e5e6190fa864d58f7ee3820f42d92673' 
  AND token = 'DxiSWU4p8uLfwUjT5Y2BTEdDGXBZpCMp/ACllJHsbKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}