Envconsul using environment variables


I have this key value in consul
$ consul kv get console/mix_env
result ==> prod

I want to use an environment variable like this to overwrite the consul value
$ MIX_ENV=staging envconsul -prefix console -upcase env | grep MIX_ENV
result ==> MIX_ENV=prod

My intention was to force MIX_ENV=staging.

As far as I know envconsul let do this unless -pristine param is used.

Am I right?