For some reason, clamscan needs too much time to scan small file.

For example, I scanned GLAT Client malware (https://notabug.org/GLAT/glat-client, please send it to anti-malware companies, it is scam scareware).

File is very small (0.01 MB), but ClamAV scanned it for 228.667 sec (3 m 48 s).