[{"exchanges":{"3478956c-3a01-404f-84e7-2a076e165215":{"foo":1},"69714c71-d86c-485b-8dcc-3fc3d0490877":{"foo":2},"c1afb435-281d-4a91-afd4-d6694cad9e20":{"foo":3}}},{"exchanges":{"3478956c-3a01-404f-84e7-2a076e165215":{"foo":4},"1e1d1efb-5bf9-48ac-93ca-4a2df5a9f7eb":{"foo":5}}}]

db.collection.aggregate([{"$project":{"exchangesAsArray":{"$objectToArray":"$exchanges"}}},{"$match":{"exchangesAsArray":{"$not":{"$elemMatch":{"k":{$nin:["3478956c-3a01-404f-84e7-2a076e165215","1e1d1efb-5bf9-48ac-93ca-4a2df5a9f7eb","69714c71-d86c-485b-8dcc-3fc3d0490877","c1afb435-281d-4a91-afd4-d6694cad9e20"]}}}}}}])