SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36c28b28da23af2c939b19cb0ecfaa6a740e01989f73b9189c262871aeace178' 
  AND token = '99EJU/TfcJbYeSdVFsE2pFZYruKOUzvVh4xSorvkaOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

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