Is there a simple way to find Software Testing risk in five minutes?

YES.

It might take less the 5mins , if you have some basic data with you.

Group number of tests by Software Testing Functional areas.
( total tests and tests completed at that point)
Find % of tests completed per Functional area

Group number bugs found per Functional area at that point.
Find % of bugs per Functional area.

If % of bugs per functional area is more than % of tests completed
in the same functional test area consider there is a Software Testing RISK.

Act accordingly.