Elasticsearch query without date range

Elastic Stack Elasticsearch
5

Okey, here is my question: if I define the parameter "size" in the query below, will it be faster? If not how can I make faster that query?

query: {
  bool: {
    must: [
      {
        bool: {
          should: [
            {
              match_phrase: {
                logTag: LOG1
              }
            }
            {
              match_phrase: {
                logTag: LOG2
              }
            }
          ]
          minimum_should_match: 1
        }
      }
    ]
    filter: [
      {
        range: {
          @timestamp: {
            lte: 
             "2020-10-24T08:19:39.438Z"
          }
        }
      }
    ]
    should: [
    ]
    must_not: [
    ]
  }
}
aggs: {
  status: {
    top_hits: {
      docvalue_fields: [
        {
          field: Severity
          format: use_field_mapping
        }
      ]
      _source: [
        Severity
      ]
      size: 1
      sort: [
        {
          @timestamp: {
            order: desc
          }
        }
      ]
    }
  }
}