How long is a machine recovery response code valid to sucessfully unlock a client ?
There is not an exact option refering that but according to my observations it could be up to 10 minutes.
It could also be referred to below policy option:
You can raise a product idea in case you think that option could be useful:
Download the new ePolicy Orchestrator (ePO) Support Center Extension which simplifies ePO management and provides support resources directly in the console. Learn more about ePO Support Center