code: func (s *ProvisioningService) GetToken(token string) (services.ProvisionToken, error) {
  	if token == "" {
  		return nil, trace.BadParameter("missing parameter token")
  	}
  	item, err := s.Get(context.TODO(), backend.Key(tokensPrefix, token))
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  	return services.UnmarshalProvisionToken(item.Value, services.SkipValidation(),
  		services.WithResourceID(item.ID), services.WithExpires(item.Expires))
  }
docs: // GetToken finds and returns token by ID