SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86272eacb124ef59de72056392c98506678db0554a864bf08ec835054f679c71' 
  AND token = 'IS/m93x4F75HPbIq+E6EDUriiyBakkIfaNfg27zOk8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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