SELECT 
  lang.value 
FROM 
  cscart_language_values lang 
WHERE 
  lang.lang_code = 'en' 
  AND lang.name = 'abt_menu_ajax_load.tooltip'

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "1.00"
    },
    "table": {
      "table_name": "lang",
      "access_type": "const",
      "possible_keys": [
        "PRIMARY"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "lang_code",
        "name"
      ],
      "key_length": "392",
      "ref": [
        "const",
        "const"
      ],
      "rows_examined_per_scan": 1,
      "rows_produced_per_join": 1,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "0.00",
        "eval_cost": "0.20",
        "prefix_cost": "0.00",
        "data_read_per_join": "408"
      },
      "used_columns": [
        "lang_code",
        "name",
        "value"
      ]
    }
  }
}

Result

value
Use Ajax to get the content of the second and third menu levels after page loading. The content of the first level will be loaded along with the page main content