Lock whole sheet after a specific date

I have a workbook with tabs representing each month of the year. On a given month, staff are allowed to enter information in specific columns housed inside a table. They have until the 5th of following month to enter their info. Each sheet is protected and have both locked and unlocked cells. I would like to make the unlocked cells (really all cells) locked on the 6th of following month. The date of month is in A1 of each tab (January = 1/1/22, February 2/1/22).

Anything with *** I am not sure of the correct code:
Sheet1.Select
Sheet1.Unprotect "$$$"
Sheet1.ListObjects("Table1").Range.Select
***If NOW() is 1 month and 6 days after date listed in A1, then protect all cells in Table1
Sheet1.Select
Sheet1.Protect "$$$"

Thanks Sweep. I modified your code slightly to indicate expiration date as one month AND five days added to "A1" but doesn't seem to work. Can you ID my error please:

Private Sub Workbook_Open()
Call Check_Expired
End Sub

Sub Check_Expired()
Dim sh As Worksheet
Dim dExpiry As Date

For Each sh In ThisWorkbook.Sheets
sh.Unprotect Password:="password"
dExpiry = DateSerial(Year(A1), Month(A1) + 1, Day(A1) + 5)
If dExpiry <= DateValue(Now) Then
sh.Cells.Locked = True
End If
sh.Protect Password:="password"

Next sh


End Sub

Thanks Sweep