Assign time-lock to workbook to restrict access after a certain date/time

Hi There! I am trying to design a macro that will not allow the user to open a workbook after a certain date/time. There is an old post that shares the code to do something close to this, but I need to make a few adjustments to the code to fit my needs. I need help figuring out these modifications :0). Here is the old thread: Assign Expiry Date(Time-Lock) to Excel Workbook.

These are the changes I'm trying to make to adapt the code shared in this post to my needs:
1) How would I make the expiration date for a specific date and time? Isdate is used to validate whether a date is entered by the user, is there an alternative function that can handle a time in addition to the date?
2) I don't want the user to be able to view the content of the excel file after the expiration date, not just lock the cell values. Is there a way to do that?

Thanks!
Michelle