And no, youre not supposed to know what your Prize cards are, so no peeking
Creating two extra creatures for 1 mana is pretty good, and even better if youre running token doublers
Like most Magic: The Gathering cards, the value of Explore depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (The Lost Caverns of Ixalan Commander)
Its usually overshadowed by the popularity of Feather, the Redeemed as Boros commander since they play similar roles
Notice how the black of the mana symbol is completely black throughout
Every spell someone casts must be assessed on whether it's really worth one more mana or potentially giving you a card you could win the game with, and that's a lot of cognitive load to put on a player already trying to plan their turn