SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6da5924d615eba61b3b8275599f804cf216ca93ea83e223591de97b5bb7cba0' 
  AND token = '4cIFKIVkY8mP9SPh8ZoCMuqKUcpMMZ9knGQf8L+qStw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

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