SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a10d1cf9bebcd72497a2a48a654b4406a1deb08ad8f427c56bacbeb56c99a722' 
  AND token = 'UBn+dfzJ7vncHjZNZS/ehstM9mPgz5yABewKzHatZIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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