Solution:
Use following code
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /localsearch/
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /localsearch/index.php
</IfModule>
# END WordPress
########### AMEMBER START #####################
Options +FollowSymLinks
RewriteEngine On
## allow access for product #12
RewriteCond %{HTTP_COOKIE} amember_nr=([a-zA-Z0-9]+)
RewriteCond /home/www/changed.tld/amember/data/new_rewrite/%1-12 -f
RewriteRule ^(.*)$ - [L]
## if user is not authorized, redirect to login page
# BrowserMatch "MSIE" force-no-vary
RewriteCond %{QUERY_STRING} (.+)
RewriteRule ^(.*)$ http://changed.tld/amember/plugins/protect/new_rewrite/login.php?v=-12&url=%{REQUEST_URI}?%{QUERY_STRING} [L,R]
RewriteRule ^(.*)$ http://changed.tld/amember/plugins/protect/new_rewrite/login.php?v=-12&url=%{REQUEST_URI} [L,R]
########### AMEMBER FINISH ####################