There is a hidden option in the Windows 10 Advanced Power Options called ‘Console lock display off timeout’. First enable access by setting this Attributes reg key value from 1 to 2:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\PowerSettings\7516b95f-f776-4464-8c53-06167f40cc99\8EC4B3A5-6868-48c2-BE75-4F3044BE88A7]
"Attributes"=dword:00000002
Then use Windows+X, Power Options, Advanced Power Settings, Change Plan Settings, Change Advanced Power Settings. From here, under Display, you can adjust the ‘Console lock display off timeout’.