SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a733166eb9ee7397bfcf8a53df9f71e2d106fb11bfc121307f80dcb8b30cc8a' 
  AND token = 'az8XalIqme7g9VNJ4qNtHJCz8xCWG8qTtmtjeeD7hvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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