SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '863e15c627c210729b6dc48dd2f533e1300af3d984ae789daba016237cb68f90' 
  AND token = 'f84xyexomFynxdvvLRi0qpc5+jx/e6omRZIPt2DxOqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}