SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c5e7924e1761f968771f69883cc1d07b748f3882c0eb3d81d3dc85795928b2f2' 
  AND token = 'V7XY+7vaA0V3JZHpQWjLFkw4y1Bc8Bo8OcDJCEnaNdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}