RewriteEngine On 
RewriteBase /

RewriteCond %{HTTP_HOST} ^www.piedralaves.com.es [NC]
RewriteRule (.*) http://piedralaves.com.es/$1 [R=301,L,QSA]

RewriteCond %{SERVER_PORT} 80
RewriteRule ^(.*)$ https://piedralaves.com.es/$1 [R=301,L,QSA]

ErrorDocument 404 /index.php