A much faster method on windows (0.05s), call a bat script that does this:
get_latest.bat
@echo off
for /f %%i in ('dir \\directory\in\question /b/a-d/od/t:c') do set LAST=%%i
%LAST%
where \\directory\in\question is the directory you want to investigate.
get_latest.py
from subprocess import Popen, PIPE
p = Popen("get_latest.bat", shell=True, stdout=PIPE,)
stdout, stderr = p.communicate()
print(stdout, stderr)
if it finds a file stdout is the path and stderr is None.
Use stdout.decode("utf-8").rstrip() to get the usable string representation of the file name.