Setting workspace_key_prefix using environment variables?

Is it possible to set workspace_key_prefix using environment variables?

I have a common Gitlab template that I maintain for my team that removes a lot of the complexities of terraform in ci/cd.

But when using workspaces, I would like to enforce a common workspace_key_prefix.
I’ve tried using TF_VAR_ workspace_key_prefix but that doesn’t seem to work.
Is there an equivalent for setting backend config args?