Prometheus query for metrics generation

I’m collecting metrics with Prometheus, specifically histograms of outgoing requests from my service to various routes.

Here’s an metric example:

southbound_request_duration_seconds_bucket{le="0.05",target="",method="GET",route="",status_code="200",type="total"} 96

I wish to display in a grafana metrics by route & by latency percentile.

This is the query I wrote:

histogram_quantile(0.90, sum(rate(southbound_request_duration_seconds_bucket{marathon_app_path=~"$instance_path", route=~"$route", env="mars"}[1d])) by (route))

but for some reason i does not generate any data. If I replace
by (route) to by (le)
It generates data but every percentile appears 3 times (one per each route) but it does not display the actual route.

Please advise