SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27f3ed0fc15986b91e9892afc8b2d7b128511613b0c80ddbb84f1648bd3c5118' 
  AND token = 'WGz6AYBaVdGyM/ZrLIeDirrIyofGHrordQWB9qia6+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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