Some handy considerations when running WP_Query to speed up the query depending on the requirements. This demonstrates using specific post ID's from ACF custom database tables in conjunction with some built in WP_Query args to save on internal queries.

wp-query-efficiency-args.php

<?php 

$query = new WP_Query([
  
  // Standard query args. Using post__in can be much faster. If searching ACF custom 
  // database tables data, plugin the found post IDs in here.
  'post_type' => 'post',
  'post__in' => [1,2,3], // array of post IDs 
  
  // Optional args to improve performance. Use these to cut down on internal 
  // complexity and make the overall internal SQL faster.
  
  // Don't need total found rows? 
  // Set this to true to save on additional queries.
  'no_found_rows' => true,
  
  // Don't need WordPress to run the meta query for all meta data for found posts?
  // Set this to false to save on additional queries. 
  'update_post_meta_cache' => false,
  
  // Don't need to worry about taxonomies for found posts? 
  // Set this to false to save on additional queries. 
  'update_post_term_cache' => false,
  
]);