NSL REST API - POST with cURL

curl-test.php

<?php
$url          = 'https://example.com/wp-json/nextend-social-login/v1/facebook/get_user';
$access_token = array(
    'access_token' => '{"access_token":"EAAKdOKespJMBAKKanbl7q4vnqvGS6JpJE1IkLIlklxkBtBjIG1u0piAQLby6fwZAj0NGtOSJqY4A6PTfpzWhx77Pci0joIb01RChGO6sMgxShXZBcfnSDBdwTLopyHrtxnCqM7OLvhCCMOaJ2RxFKSAPdqCbhWrZCMxh5w1GIPAZCGxJCKr4jVl43Ig8oCQZD","token_type":"bearer","expires_in":5108158}'
);

$ch        = curl_init($url);
$postQuery = http_build_query($access_token);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $postQuery);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);
curl_close($ch);

var_dump($response);