Some time if you are away from your mac laptop .. it keep on lock your screen but just in case if you want to keep un lock then you can do as below
https://keepingyouawake.app/
From the above link click on Download button
Unzip the the downloaded file
To start a the app you can Double click on Keeping you Awake
Once it starts you can update the settings as how long it should not be un lock
by clicking on Cup icon
If you choose Indefinitely it will alway be un locked.
It has a below Features
prevents your Mac from going to sleep with one click
pre-defined activation durations
can disable itself when the battery level is low
supports Retina displays and Dark Mode
supports macOS Big Sur and all versions since macOS Sierra
translated into various languages by the community