SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '249d5f260c2a797f1f298225474b9b9dbd540e7f16a32761662f8e5b1fe0b578' 
  AND token = 'cFon1sgFIJO8XwKoWcCkJiTcBSmz8M0OIw8RKIvD/hQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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