SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4cae25683577c0ce298d182af544538782c6f468b7b1084c893817bdf18895b' 
  AND token = 'f/pNw3DM1H4ci03HR8MFHLOjcjSV2hLaX7tu0b0TSj4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

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