latest.php

<?php
/**
 * 
 */
public static function get_rule_logs( $query  ) {

  if (!isset($query['rule_id']) || !$query['rule_id']) {
      return [];
  }

  global $wpdb;

  $table_name = $wpdb->prefix . "logs WHERE 1=1 ";

  $query = 'SELECT * FROM '.$table_name;
  $args = [];

  if (isset($query['rule_id']) && $query['rule_id']) {
      $query .= ' AND rule_id = %d ';
      $args[] = $query['rule_id'];
  }

  if (isset($query['begin_date']) && $query['begin_date']) {
      $query .= ' AND datetime >= %s ';
      $args[] = $query['begin_date'];
  }

  if (isset($query['end_date']) && $query['end_date']) {
      $query .= ' AND datetime <= %s ';
      $args[] = $query['end_date'];
  }

  return $wpdb->get_results( $wpdb->prepare( $query , $args ) , ARRAY_A );
}

The difference between append and implode is more visual :)

The dummy 1 = 1 looks horrible while the implode solution is more "object-oriented", but is just a personal taste