MySQL uses intersection instead compound index
The selectivity has changed with the added selections.So now the optimizer will think that an intersection of indexes is more efficient than just one index.Compound indexes have a cardinality that matches all their columns,it`s not separate for column so MySQL will try to reduce this selection with an index intersection.Find out which column is the most selective(has the least values returned) and rewrite it with this in mind.

You could turn off index merge with a SESSION option but this the bulldozer approach.