What is your output resolution and CPU? 86 passes is not that much.
Some further ideas:
-revert back to default render settings
-set max sample intensity to 10 (it will make the render slightly darker, but noise will go away faster)
-place a portal as suggested https://coronarenderer.freshdesk.com/support/solutions/articles/5000501660
Yeah, that’s not a very powerful system, so it probably does not represent the expected speed of Corona. I am afraid that heavily optimizing the scene and waiting for more passes to compute could be the only solution.