SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a73d85e0f05629a6e83b8dad6659d60ea001680844dd906496b0e40698f4bf24' 
  AND token = '61xrdjWDhteu5LNgk9vL7hxPj4TbGJmrFuSymfmqK+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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