SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9b47a4710938014d9c127687a8fe660259e551396244b3fe632798f72d7f6a4' 
  AND token = 'Vuv+7Om07rN5XBfTlYz3dVdFLelY3JwobZweS/rEiFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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