SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a471cc01fd438cb1744931de30cd2592f10436a57b183cfd0e11d918c9d9c1b3' 
  AND token = 'IsDymkwDQzdWjKIyePYM+/bUhpF6Xz/drWdEB7GzNPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

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