Postman and Google Cloud platform private keys

We have an API endpoint that is running on Google cloud platform and that endpoint writes stuff to Google BigQuery. So we have a never expiring Bearer token that we use to talk to the API endpoint.
I am writing some automated test using Postman to make API calls to the endpoint and BigQuery as well. So the problem that I am having is Google has something called service account (private key) in form of .json file. So right now I don’t see postman support this for Google cloud platform. So as a workaround using the Google service account I am generating a Bearer token and using that making a query to BigQuery but that token expires in 1 hour and I have to manual generate a token again(GOOGLE_APPLICATION_CREDENTIALS=~/<path-to-service-accout.json> gcloud auth application-default print-access-token) to run the automated test. My Question is

  1. is there a way using postman app and Google service account( google private keys) I can have my tests run without user intervention?