SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7fc31ea630e94908b9dfedd10d3ec03509ccc72a387e2b412de346c6cc00787' 
  AND token = 'm5Rz34mesjrEgYkZhDiXoZAsNirBv6x5fcgQ9hvY9A4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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