SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df30f519e587cacaf7b805514f8326554603b16c50a3cf27ba12e61bfeed432f' 
  AND token = 'A4YQTe5pDj6SSBhh+kToKDTAkRROe7ybMLpQRGaTwyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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