SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15cbae15bc1340a967fc373e0241e8975a1b83d5b9d35b400c243db1b2095a90' 
  AND token = '1MmEiy5hVC6mBxViE2beUrCpM5wSLVvzRAlh3z7zwBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

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