It can be done in nginx using geoip2 module.

this block goes to http { part of config, for example

/etc/nginx/conf.d/geoip.conf

geoip2 /usr/share/GeoIP/country_asn.mmdb {
     # if you have some database update script, you can configure auto reload
     # auto_reload 1h;
     $geoip2_asn asn;
     $geoip2_as_name as_name;
     $geoip2_continent continent;
     $geoip2_continent_name continent_name;
     $geoip2_country country;
}

And use it in location

put this in location

if ($geoip2_asn = "AS32934") {
    return 402;
}