Is it to soon for flower boxes in NY?

Sorry, but its just way too cold still in your area. You should wait until temperatures are consistently above 40F because a hard freeze (below 30F) will damage or kill them. Pansies can withstand cold temperatures and you probably can plant those now. Mine survived the entire winter in a pot (with damage, but it was a cold winter with record snow) and it even opened up another flower today proving how hardy they are). I wouldn't recommend planting them as spring flowers because they die out when the warm summer weather comes.