More efficient way to get metadata on files in search
Search by metadata returns a list of files. That list isn't much use without knowing the metadata it matched. To use Box's metadata for anything past the initial search query that's related to display, each individual search result must be queried for its metadata.
We are now in the process of rolling out the new Metadata Query capability to all Box enterprises and expect to be complete by the end of June 2020.
Please refer to https://developer.box.com/guides/metadata/queries/