SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5448b7e8459298f65222623f40842cc5c1e63dd4f1474f24b7c063b2395f2970' 
  AND token = 'CnSmo3NQVGIeBKTYM8yE69pZzDqz41fUGg9lpY+2QJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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