The Treasury
Scholars have said that seeing oneself opening a treasury door with a key and taking out jewels in a dream may indicate asking a scholar about academic matters, as a scholar is like a treasury and questioning is its key. This vision may also indicate marrying a beautiful woman and being blessed with beautiful children.
Per Ibn Sirin's Muntakhab al-Kalam fi Tafsir al-Ahlam
Note: These are traditional scholarly interpretations (ijtihad) drawn from a specific classical source — not a binding religious ruling, fortune-telling, or a prediction of the future.