Get all raw session meta from all wordpress users.

wp-session-display-cookies.php

<?php
/**
 * Get all raw session meta from all users
 *
 * @return array
 */
function readlimit_get_all_sessions_raw() {
	global $wpdb;

	$results  = array();
	$sessions = $wpdb->get_results( "SELECT meta_value FROM $wpdb->usermeta 
									WHERE meta_key = 'session_tokens' LIMIT 0, 9999" );
	$sessions = wp_list_pluck( $sessions, 'meta_value' );
	$sessions = array_map( 'maybe_unserialize', $sessions );

	foreach ( $sessions as $session ) {
		$results = array_merge( $results, $session );
	}

	return (array) $results;
}

/**
 * Debug routine for exposing user sessions in admin
 *
 */
function readlimit_get_users_with_sessions(){

	$args = array(
		'number'     => 9999,
		'blog_id'    => is_network_admin() ? 0 : get_current_blog_id(),
		'meta_query' => array(
			array(
				'key'     => 'session_tokens',
				'compare' => 'EXISTS',
			),
		),
	);

	$users = new WP_User_Query( $args );
	return $users;

}

/**
 * Get all sessions from all users
 *
 * @return array
 */
function readlimit_get_all_sessions() {
	$results  = array();
	$users    = readlimit_get_users_with_sessions()->get_results();
	$sessions = readlimit_get_all_sessions_raw();
	//$results  = array();
	$test = $_COOKIE['readlimit-readlimits'];
?>

<table class="widefat fixed" cellspacing="0">
    <thead><tr>
    
        <th>user_id</th>
		<th>_session->login</th>
		<th>_session->expiration</th>
		<th>token_hash</th></tr></thead><tbody>

	<?php  
	echo '<tr><td colspan="4">rls: ' . $test . '</td></tr>';

	if ( ! empty( $users ) ) {
	
	foreach ( $users as $user ) {

		$user_sessions = get_user_meta( $user->ID, 'session_tokens', true );

		foreach ( $sessions as $session ) {
			foreach ( $user_sessions as $token_hash => $user_session ) {
				// Loose comparison needed
				if ( $user_session != $session ) {
					continue;
				}
				echo '<tr><td>' . $user->ID . '</td>
					<td>' . $user_session['login'] . ' created ' 
					. human_time_diff( $user_session['login'] ) . ' ago</td>
					<td>' . $user_session['expiration'] . ' exprs in ' 
					. human_time_diff( $user_session['expiration'] ) . '</td>
					<td>' . $token_hash . '</td></tr>';
			}
		}
	} 
	
	} else { 

        echo '<tr><td colspan="4">No sessions found.</td></tr>';
    
    } ?> 
    
    </tbody></table>
    <?php 

}

//add_action('readlimit_session_handler', 'readlimit_session_handler_onlogin' );
// debug shortcode
function readlimit_show_cookie_form() { 

    //$readlimit_login_time = get_user_meta( $user->ID, 'last_login', true ); 
    $readlimit_readlimit_val = ''; //readlimit_get_cookie();
	ob_start(); 
		
        readlimit_get_all_sessions();
	    
		return ob_get_clean();
} 
// Shortcode to display table layout of sessions
function readlimit_register_shortcodes() {
    add_shortcode( 'rrcookie_form', 'readlimit_show_cookie_form' );
}
    add_action( 'init', 'readlimit_register_shortcodes' );