SELECT 
  settings 
FROM 
  cscart_ath_mega_menu 
WHERE 
  company_id = 1

Query time 0.00010

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_ath_mega_menu",
          "access_type": "system",
          "possible_keys": ["PRIMARY"],
          "rows": 1,
          "filtered": 100
        }
      }
    ]
  }
}

Result

settings
{"menu_bg":"#9f81bf","menu_linkl1":"#fff","menu_linkl1_hover":"#6200ee","menu_dd_bg":"#fff","menu_linkl2":"#222","menu_linkl2_hover":"#6200ee","menu_borders":"#ebebeb"}