SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11dc2d82c2e57a88a4f73b091df8a41a5857714fdb972a8072e3718975ee2c42' 
  AND token = 'mLmcZ+IsL549E4dSfUiF2D0RZU1KtRoGYdsqrPP5Eac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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