SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '406a7f4c4342bd7e061ec6c5aa56aa7ee03c3769cbd1da0343e1806d4dd9d39c' 
  AND token = 'CumxbtUqfTw3Y7SyUqpStVqTtIVTUdMP6n8LREl0k+k=' 
  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