code: protected function getMetaBetweenConstraint($column, array $values)
      {
          $min = $values[0];
          $max = $values[1];
  
          return function ($query) use ($column, $min, $max) {
              $query->where('meta_key', $column)
                  ->where('meta_value', '>=', $min)
                  ->where('meta_value', '<=', $max);
          };
      }
docs: Query Builder whereBetween override required to pass raw numeric values.
  
  @param  string $column
  @param  array  $values
  @return \Closure