index.php

<?php

//define post type
'post_type' => 'post',

//Disable cache
$query = get_posts( array( 'posts_per_page' => 1, 'cache_results' => false ) );

//No terms cache
'update_post_term_cache' => false,

//Meta cache
'update_post_meta_cache' => false,

//No pagination
$query = new WP_Query( array( 'posts_per_page' => 1, 'no_found_rows' => true ) );

//Only post ID
$query = get_posts( array( 'posts_per_page' => 1, 'fields' => 'ids' ) );

?>