$url = 'https://neowebinar.cz/oauth/token';
$webinar_client_id = "1";
$webinar_client_secret = "9EyOZBQT1C03JWV8eVlmstioTDM9BhzXHZ0Vehe7";

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, 1);

curl_setopt($ch, CURLOPT_POSTFIELDS,"client_id=".$webinar_client_id."&client_secret=".$webinar_client_secret."&grant_type=client_credentials&scope=*");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$output = curl_exec($ch);
$output = json_decode($output);

echo curl_getinfo($ch, CURLINFO_HTTP_CODE);
var_dump($output);