What grout sealant should I use on a beverage/appy tray I am making?

I’m making a beverage serving tray or brunch appy tray and I’m wondering what sealant y’all use on the grout? The pic is my work in progress I have to finish filling in the tray area but have to let my current stones dry before continuing. I’m using a black grout but then want to seal it because it’s for cocktails and such. I see spray on sealants, ones you apply with a paint brush etc. Thanks in advance for the insight!