RewriteEngine On
RewriteCond %{HTTPS} =off
RewriteCond %{HTTP:X-Forwarded-Proto} !https
RewriteCond %{REQUEST_METHOD} !POST
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [R,L]
RewriteCond %{HTTPS} =off
RewriteCond %{REQUEST_URI} ^/admin/$
RewriteRule (.*) http://%{HTTP_HOST}%{REQUEST_URI} [R,L]
<head>
шаблона главной и шаблона внутренних страниц просто прописал: <link rel="canonical" href="https://my.site.ru/" />
<link rel="canonical" href="https://my.site.ru/" />