SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38bab7d51bd2a2ddc74ef02093b6950c1cfafbc8711ccffebdfc775a8de2804c' 
  AND token = 'OlZXcVehMuCMk1c0djmH8hFn/NGFpMvXJGMX9IWiPO4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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