As a MalwareBytes
Premium user (which automatically updates and scans every hour or so) your post raised my curiosity and searched
MalwareBytes threats and ClamXV for silver sparrow and neither currently identifies silver sparrow in its Mac threat list. Therefore it is not unreasonable to conclude they likely have no
signature for silver sparrow yet, and without the silver sparrow
signature neither product can detect it. So although both products gave your system a one shot clean bill of health it is likely meaningless as far as a potential silver sparrow infection. Even if they did have the silver sparrow signature a one shot scan does not mean you system is still clean even minutes after such a scan.
Just saying.
NOTE: Threat lists can be deceptive because not everyone uses the same name for a given threat although silver sparrow is getting enough press that is less likely.