从WordPress查询中排除密钥

Question

$counter = 1;
$grids = 3;
$titlelength = 30;

$args=array (
    'post_type' => 'product',
    'orderby'    =>  'date',
    'posts_per_page' => 9,
    'tax_query' => array(
    'relation' => 'OR',
     array(
     'taxonomy' => 'herkunft',
     'field' => 'slug',
     'terms' => 'deutschland'
     ),
    array(
    'taxonomy' => 'herkunft',
    'field' => 'slug',
    'terms' => 'oesterreich'
     ),
array(
    'taxonomy' => 'herkunft',
    'field' => 'slug',
    'terms' => 'schweiz'
 ),
)   
);

请参阅上面的查询。是否可以从查询中排除key => 'product_fake'（自定义帖子类型'products'的一部分），我该怎么做？