Hi Vegetables and welcome to GoY. To be honest I'm not sure, Laburnum is very toxic and I wonder if the seeds will even break down. At the same time the toxicity is to humans and animals not other plants. I 'think' you 'should' be okay but would wear latex gloves when working with the compost.

If it is a recent variety, Laburnum x watereri 'Vossii', then the pods will have very little or no seed in them so they will not be a problem when handling or composting. The seeds will only be a problem it eaten.

Only lethal if seeds, bark, twigs etc are consumed/eaten. Every part of this plant is toxic if eaten directly. I don't believe it is harmful to use in a log burner or open fire or even as part of the compost heap - just don't eat it!!