SELECT 
  * 
FROM 
  cscart_profile_fields 
WHERE 
  profile_type = 'S'

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "5.21"
    },
    "table": {
      "table_name": "cscart_profile_fields",
      "access_type": "ALL",
      "rows_examined_per_scan": 45,
      "rows_produced_per_join": 4,
      "filtered": "10.00",
      "cost_info": {
        "read_cost": "4.77",
        "eval_cost": "0.45",
        "prefix_cost": "5.22",
        "data_read_per_join": "4K"
      },
      "used_columns": [
        "field_id",
        "field_name",
        "profile_show",
        "profile_required",
        "checkout_show",
        "checkout_required",
        "partner_show",
        "partner_required",
        "storefront_show",
        "field_type",
        "profile_type",
        "position",
        "is_default",
        "section",
        "matching_id",
        "class",
        "wrapper_class",
        "autocomplete_type"
      ],
      "attached_condition": "(`s2cart`.`cscart_profile_fields`.`profile_type` = 'S')"
    }
  }
}