wp_query using post_id

I want to retrieve the post using the post id.
But i found that its retrieving the post based on custom post type and not by post id. This my code. Please give me some suggestions.

$args = array(
	    'post_type' => 'landingpage',
            'post_id' => '4110',
	    'post_status' => 'publish',
	    'meta_query' => array(
	       						 'relation' => 'AND',
							        array(
							            'key'     => 'page_link',
							            'value'   => 'https://5.heypayless/Landing%20Pages/dedicated-web-programmers/',
							            'compare' => '='
							      )
						    )    

	);

	   $obituary_query = new WP_Query($args);
	while ($obituary_query->have_posts()) : $obituary_query->the_post();
		$test= get_field('price/hr_for_test_services');
		$junior=get_field('price/hr_for_junior');
		$senior=get_field('price/hr_for_senior');
		$lead=get_field('price/hr_for_lead_designer');
		$features=get_field('features_for_test_services');
		$features2=get_field('features_for_junior');
		$features3=get_field('features_for_senior');
		$features4=get_field('features_for_lead_designer');
	endwhile;
	 echo $post->ID;
	wp_reset_postdata();

	?>