SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ee3f7bd4f7999518905701af002617bfa7daa3aad8a59b47ed882341036659f' 
  AND token = 'Rue5MRFrO555kEk5M8ZB95amtPSHvcDM4Qrs72OYMlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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