SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9db5c88f8c4ef20c900bb53f1ad4ea78b5e2e582f22439bcd32ad6497ccc951' 
  AND token = 'vlf+62+B6qpgoWhBTozF4KaZYckXhEXvmto2+UkVdX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables