SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd923b6a53406d7d4a4bbfdbee06688251c3ccc302f7aa19c175b775039697c58' 
  AND token = 'IiPeE2tbowgd05Bu04/uAqYaqa9ujPOWwKRmxbPRp3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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