SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93018e613daea96f849e21b2b4eefda54a870724f8b9f9edcc4a24d8574258cc' 
  AND token = 'wWSFrtihbK+eVvksLm+7+epGPuOlGjsgXAzU1Dnl+1s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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