Rooting Moloch gives you permission to play the card as a land or cast it as a spell. You can’t cycle the exiled card.
2020-04-17 • wotc
You must follow the normal timing permissions and restrictions for the exiled card. If it’s a land, you can’t play it unless you have land plays available.
2020-04-17 • wotc
You’ll still pay all costs for a spell cast this way, including additional costs. You may also pay alternative costs if any are available.
2020-04-17 • wotc
If you don’t play the exiled card, it remains exiled.