SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b43b1cf1c5fc3f6cc0a83413a3fc16f7c3e5cb41e1550255eed6c2d04497e629' 
  AND token = '4X7sL7z8VHwDoIVDvsj5Ki6LvJ1gmgCtBY+u5geiHtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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