SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff0cf97e09f9788e30de29f24c668e7afeac3c9b49f305202de4464b08682e9d' 
  AND token = 'DplIMSkv1yieENJKosu0exT1DMTyeHwJc3KLRP0CPEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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