I’m pretty sure this doesn’t exist as an option unfortunately, though it could be done with a fairly trivial modification to the code: grafana/rangeOptions.ts at master · grafana/grafana · GitHub (after which you’d need to compile of course).
Alternatively you could look at the Grafana JS files on your server (if you have access to them) and search for e.g. “Last 5 minutes” to see where the time ranges are defined and modify the definitions there (likely app.xxxxxx.js). Have in mind this would of course get wiped if you upgrade Grafana.
Or create a Github feature request to add this as a config option (assuming one doesn’t already exist).