[{"terms":{"hash1":{"some":"value",},"hash2":{"another":"value",},"hash3":{"another3":"value3",}},"keys":["hash2","hash3"]}]

db.collection.aggregate([{"$project":{"terms":{"$objectToArray":"$terms"},"keys":1}},{"$project":{"filteredTerms":{"$filter":{"input":"$terms","as":"array","cond":{"$in":["$$array.k","$keys"]}}}}},{"$set":{"filteredTerms":"$filteredTerms.v"}}])