SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f04a10870eec924c9ffef2441e07fcf7f72c3d9283ba9718f651faa8b6adb52f' 
  AND token = '36TB/RkHsrIcTS8TNGHCv1TwXxxTNuG7riOyliKrl4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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