NGINX sha256 path matching file directory

nginx.site.conf

server {
        listen 80;
        listen [::]:80;

        server_name website.com;

        access_log  /var/log/nginx/website.access.log;
        error_log  /var/log/nginx/website.error.log;

        client_max_body_size 20m;

        location /folders {
                set $lpc "ingenting";
                if ($uri ~* "^/folders/([a-z,0-9]{64}/.*)" ) { # this tends to be constant time
                   set $lpc $2;
                }

                alias /var/www/folders/$lpc; # folder or symlink with sha256 as name contained here

                autoindex on;
                autoindex_format xml;
                xslt_stylesheet /var/www/dirlist.xslt path='$uri';

        }

        location / {
                 root /var/www/html;
        }

        error_page 404 /404.html;
        location = /404.html {
            root  /var/www/html;
            internal;
        }
}