SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fa82944b1e1dc39d95b94ba159d8fec709aa07e76421518390e26f36f5609ef' 
  AND token = 'qnzGLeBgsRThD+PXExMc57lPA2q2yn8yswiTmx+uu6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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