We can probably add a column and search type for that in Opus 13, as that is using MediaInfo now. (We've added a bunch of other columns, but that wasn't one I'd thought of.)
In the shorter term, or if you don't want to use the 13 public beta, I bet ExifTool and @Lxp's ExifTool Custom Columns script can get the data. In the Find/Advanced panel, you could then add a Script Column comparison to the filter.
These may also come in handy, if you want to go the script route:
- ExifTool MKV data/keywords: Matroska Tags
(Other types it handles: ExifTool Tag Names ) - PrintMeta (Write metadata to text files) is another script by @Lxp which can output all the metadata ExifTool (or MediaInfo) can output for a file, which can be a quick way to find the right keyword for the data you need, and verify the data is what you expect.