Cursed one-liner:

(Get-Date).AddMinutes(((cscript //nologo c:\windows\system32\slmgr.vbs /dlv
| Where-Object { $_ -like 'Timebased*' }) -replace '^T.*: ([0-9]+).*','$1'))

Don't mind me forgetting that there are CIM queries for this that don't require mangling console output.