SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e2e6c57b67ab73cf99fe3490001740c9814bb5359e811bd7f835bf26448585d' 
  AND token = 'KMNXnVL+qp/KtguphQRSGUyROuwIFnbmKktABvmC2GE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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