php-fpm unix domain socket (UDS)

Apache

<FilesMatch "\.php$">
  SetHandler "proxy:unix:/var/run/php-fpm/www.sock|fcgi://localhost"
</FilesMatch>

<LocationMatch "/fpm-status">
  ProxyPass "unix:/var/run/php-fpm/www.sock|fcgi://localhost"
</LocationMatch>

Unixソケットを使っている場合は以下のようになる。
httpd.conf

<FilesMatch \.php$>
    SetHandler "proxy:unix:/var/run/php-fpm/php-fpm.sock|fcgi://localhost"
</FilesMatch>

ApacheでPHP-FPMを動かすなら、ProxyPassMatchではなくSetHandlerを使うのがいいらしい - Qiita 2015

https://serverfault.com/questions/1044315/syntax-of-apache-sethandler-directive-when-configuring-php-fpm

The following example passes the request URI as a filesystem path for the PHP-FPM daemon to run. In this case, PHP-FPM is listening on a unix domain socket (UDS). Requires 2.4.9 or later. With this syntax, the hostname and optional port following fcgi:// are ignored.

PHP-FPM with UDS

ProxyPassMatch "^/(.*\.php(/.*)?)$" "unix:/var/run/php5-fpm.sock|fcgi://localhost/var/www/"

https://httpd.apache.org/docs/2.4/mod/mod_proxy_fcgi.html

nginx

nginx + php-fpm socketで接続する - Qiita 2014