SELECT 
  * 
FROM 
  cscart_abt__ut2_settings 
WHERE 
  lang_code = 'en' 
  AND storefront_id = 1

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.081104,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_abt__ut2_settings",
          "access_type": "ALL",
          "loops": 1,
          "rows": 410,
          "cost": 0.081104,
          "filtered": 100,
          "attached_condition": "cscart_abt__ut2_settings.storefront_id = 1 and cscart_abt__ut2_settings.lang_code = 'en'"
        }
      }
    ]
  }
}