SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '404149313983fba5eaacf96ec92040fcd30da2a5dbfb8f8dba70ff58da78c209' 
  AND token = 'KVeyjEAPjXtg+QhLrawrxjEehnMqbTKooyJgqD7evsU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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