Is there any butter in the refrigerator?

Literal

Refrigerator [in-に] butter [topic-は] exists [question-か].

A plain existence question. Note the は after バター — a contrastive topic, implying 'butter specifically (as opposed to something else).' Without the は, it would be a neutral 'does butter exist?' — with it, the speaker is asking about butter as a particular item of concern.