SELECT 
  bld.meta_description, 
  bld.title 
FROM 
  cscart_bm_layouts l 
  LEFT JOIN cscart_bm_locations lo ON l.layout_id = lo.layout_id 
  LEFT JOIN cscart_bm_locations_descriptions bld on lo.location_id = bld.location_id 
WHERE 
  l.storefront_id = '1' 
  AND l.theme_name = 'poscentral_store' 
  AND lo.dispatch = 'index.index' 
  AND bld.lang_code = 'en'

Query time 0.00090

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "8.40"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "l",
          "access_type": "ALL",
          "possible_keys": [
            "PRIMARY",
            "layout_id"
          ],
          "rows_examined_per_scan": 63,
          "rows_produced_per_join": 0,
          "filtered": "1.59",
          "cost_info": {
            "read_cost": "7.21",
            "eval_cost": "0.10",
            "prefix_cost": "7.31",
            "data_read_per_join": "599"
          },
          "used_columns": [
            "layout_id",
            "theme_name",
            "storefront_id"
          ],
          "attached_condition": "((`poscentr_upgrade422`.`l`.`storefront_id` = 1) and (`poscentr_upgrade422`.`l`.`theme_name` = 'poscentral_store'))"
        }
      },
      {
        "table": {
          "table_name": "lo",
          "access_type": "ref",
          "possible_keys": [
            "PRIMARY",
            "idx_dispatch_layout",
            "idx_dispatch_default",
            "idx_layout"
          ],
          "key": "idx_dispatch_layout",
          "used_key_parts": [
            "dispatch",
            "layout_id"
          ],
          "key_length": "199",
          "ref": [
            "const",
            "poscentr_upgrade422.l.layout_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "0.63",
            "eval_cost": "0.10",
            "prefix_cost": "8.04",
            "data_read_per_join": "239"
          },
          "used_columns": [
            "location_id",
            "dispatch",
            "layout_id"
          ],
          "attached_condition": "(`poscentr_upgrade422`.`l`.`layout_id` = `poscentr_upgrade422`.`lo`.`layout_id`)"
        }
      },
      {
        "table": {
          "table_name": "bld",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "location_id",
            "lang_code"
          ],
          "key_length": "10",
          "ref": [
            "poscentr_upgrade422.lo.location_id",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "index_condition": "(`poscentr_upgrade422`.`lo`.`location_id` = `poscentr_upgrade422`.`bld`.`location_id`)",
          "cost_info": {
            "read_cost": "0.26",
            "eval_cost": "0.10",
            "prefix_cost": "8.40",
            "data_read_per_join": "248"
          },
          "used_columns": [
            "location_id",
            "lang_code",
            "title",
            "meta_description"
          ]
        }
      }
    ]
  }
}