SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68a67759425ffe3612e627ffdff272d6a590cea620edf1cfb65d5835dea3e247' 
  AND token = '2Dg1Oe4ep8Zjl4KUKjsKzxlUuDn/vBjTokFwqDX++Fs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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