Afaik ruby's TIME class is not available in scripts so you can't do scheduling in scripts that way.
So you need to create a to get the correct time reliably and in a way that's paresable in scripts.
Which means passing in the time from the frontend.
You need a time app|service to get the proper time and NOT the customers browser time.
Add the correct time as a line item property, or as a cart attribute to pass from the cart to checkout, or use ajax in the checkout templates.
Alternatively setup a literal product to use as your indicator for logic in scripts and autoadd it to the cart. Either as some empty free thing labeled like "limited offer", "holiday special" etc or some spiff product like free stickers.