SELECT 
  COUNT(*) 
FROM 
  cscart_vd_vendors AS vd 
WHERE 
  1 
  AND vd.is_approved = 'A'

Query time 0.00052

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "vd",
          "access_type": "ALL",
          "rows": 283,
          "filtered": 100,
          "attached_condition": "vd.is_approved = 'A'"
        }
      }
    ]
  }
}