SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae903ef23d3cc9270ccb87ead356902471aa506f08623f01e147d15d5b50c7c1' 
  AND token = 'Jko8BXmRpPzEm8Vm3nvQ62QGph6ltBHjlJY3ejVayZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

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