SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd66c069c4de7c826ee0db91aff3fae91b2b43a3fef37b8a19ce9ef31b44a7cc0' 
  AND token = '+Z9Lgqe/CszoW0WbZGTLnugBb8QWcbnhAxggMQK6BrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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