SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4acf8b5a1c993b80a3264bc1a2ecb983757b809eb1b63d3bacd82a19c4d8e525' 
  AND token = '2UZztJ4Tl843GWH9jHLg+uQg5ILGwARaHY3Q9759DrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

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