Yes, they can!
The feature that controls this is called "Advance Ordering" and is disabled by default. To enable it, you just need to go to Settings-->General Settings from the top menu of your Paytronix Order & Delivery control panel. At the bottom of the first section ("Restaurant Information"), you'll see an "Allow Advance Orders" option:
Simply check the box as shown above and click the Save Settings button at the bottom of the page, and that's it!
Now, the next time a customer visits your menu during non-business hours, they'll get a popup window just like this one:
The date and time will default to the next time the store opens but allows the customer to select any future time they wish (within normal business hours). Once the customer clicks Ok, they will be able to continue with the regular ordering process.