In the promo, Regina says that true love’s kiss can break any curse. Since Mary Margaret and David already kissed and nothing happened, that leaves only one option. Regina needs to be kissed by her one true love to break the curse. Emma is the savior that is supposed to break the curse. I think we all see where I’m going with this.
The Queen put the curse on everyone because she was vengeful and broken and just wanted to be happy. Regina is lonely and wants love and Emma was sent to StoryBrooke to break the curse which means that she must be the key to Regina’s happiness - she must be her true love. She can break the spell by giving Regina/the Queen her happy ending. The keys Emma found, maybe those are metaphorically the keys to Regina’s heart. SwanQueen <3
…I think the writers just know how much the fandom ships them.