SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21673b12d4299fe7130de4c90622606c7aa83483bc7a4e45a16b0f03b0047af5' 
  AND token = 'JpfNpNYX2ErR3q/71qgCcSTnU1BvR1qRBv0i/KyjhsE=' 
  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