I'd like to add that both sentences are in the PASSIVE voice. So, "was changed" is the passive simple past and "has been changed" is the passive present perfect. That said, the word "does" doesn't belong. Simply: The key was changed. The key has been changed. Both of the above are grammatically correct. The question, however, is what you are trying to mean. Are you trying to ask if the key was changed or are you trying to state that it was changed? And, is it in the past or is it part of a sequence that lead to the present and therefore has relevance. To ask the question would be: Was the key changed? Has the key been changed? The difference between the two sentences is this: The key was changed = passive simple past = someone changed the key = over and done with, not important to the here and now. The key has been changed = passive present perfect = someone has changed the key in the past and it is still relevant to the here and now. Without knowing your real intent as far as present or past and whether the action is done and complete OR in the past but still relevant to now, I'm unable to be more precise. If you want, leave a note with further questions and I will explain more based on your response. I hope this helps you understand the tense and aspect system in the passive voice a little bit more. GOOD LUCK!

Past tense - the key was changed Past perfect (recently in the past) - the key has been changed. Future - stating that the key will definitely be changed on a regular basis - the key does get changed OR simple future - the key will be changed.

when I was school ’girl I had taught present perfect is atense happened in past and has result, so depend on that I can answer you (the key has been changed) and the result you found it changed