Rewrite all https to http except one location

[basti]

Hello,
I have a SSL config like

server {

 server_name ...;
 
 # do not rewrite this
 location /mailadmin/(.*.\.php)${
   ...
   # some stuff   
 }
 

 location / {
   ...
   rewrite ^ http://$server_name$request_uri? permanent;
 }

 location ~ \.php$ {
   ...
   # php stuff
 }
}

URLS like
https://example.com/mailadmin/set.php?p_s=301AB1837E730B55&framework=
are partly rewrite

How can I solve this?
Regards,
Basti