SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e945f1a2271cb0ec2620f62de6f67d47bd6d81a878d3f780698fab65352a8345' 
  AND token = 'aDTrS2s7bEeam/I78ecxDEmTL2ZFqBv6sQCBghbe7Ok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

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