SELECT 
  fontcolor, 
  backgroundcolor 
FROM 
  ushop_buynow_button 
WHERE 
  store = 1 
  OR store = 0 
ORDER BY 
  store DESC 
LIMIT 
  1

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "1.00"
    },
    "ordering_operation": {
      "using_filesort": false,
      "table": {
        "table_name": "ushop_buynow_button",
        "access_type": "system",
        "rows_examined_per_scan": 1,
        "rows_produced_per_join": 1,
        "filtered": "100.00",
        "cost_info": {
          "read_cost": "0.00",
          "eval_cost": "0.10",
          "prefix_cost": "0.00",
          "data_read_per_join": "312"
        },
        "used_columns": [
          "fontcolor",
          "backgroundcolor",
          "store"
        ]
      }
    }
  }
}