SELECT 
  COUNT(*) 
FROM 
  cscart_ec_hb_facilities 
  LEFT JOIN cscart_ec_hb_facilities_desc ON cscart_ec_hb_facilities_desc.facility_id = cscart_ec_hb_facilities.facility_id 
  AND cscart_ec_hb_facilities_desc.lang_code = 'en' 
WHERE 
  1 
  AND cscart_ec_hb_facilities.facility_id IN (2, 3, 5)

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "5.85"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_ec_hb_facilities",
          "access_type": "range",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "facility_id"
          ],
          "key_length": "4",
          "rows_examined_per_scan": 3,
          "rows_produced_per_join": 3,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "1.65",
            "eval_cost": "0.60",
            "prefix_cost": "2.25",
            "data_read_per_join": "48"
          },
          "used_columns": [
            "facility_id"
          ],
          "attached_condition": "(`atulecarter_atul_demo1`.`cscart_ec_hb_facilities`.`facility_id` in (2,3,5))"
        }
      },
      {
        "table": {
          "table_name": "cscart_ec_hb_facilities_desc",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "facility_id",
            "lang_code"
          ],
          "key_length": "10",
          "ref": [
            "atulecarter_atul_demo1.cscart_ec_hb_facilities.facility_id",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 3,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "3.00",
            "eval_cost": "0.60",
            "prefix_cost": "5.85",
            "data_read_per_join": "2K"
          },
          "used_columns": [
            "facility_id",
            "lang_code"
          ],
          "attached_condition": "<if>(is_not_null_compl(cscart_ec_hb_facilities_desc), (`atulecarter_atul_demo1`.`cscart_ec_hb_facilities_desc`.`facility_id` = `atulecarter_atul_demo1`.`cscart_ec_hb_facilities`.`facility_id`), true)"
        }
      }
    ]
  }
}