The Thai embassy in Cambodia takes 11 business days to process. They are usually good at keeping that timeline. Today was the 10th day. However, not sure if last Wednesday was a holiday or not for the embassy.
From their website, it sounds like you have to be a citizen or a resident of Spain or Andorra to apply via this embassy. Are you a citizen or a resident? (Non-Thai nationals, including citizens of Spain and Andorra, and other nationalities with residence in Spain and Andorra, who wish to apply for a Thai visa must apply and submit the application through the new online e-Visa platform)
If you are asked for more documents, you can supply them and there is no costs. If they reject or cancel your application, and you decide to re-apply, then you would need to pay the 10k again.
Alien registration card is the documentation that allows you to live in Korea. I believe if you look at the Thai embassy website for Korea only Koreans and those with legal residency can apply there.