SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a6a7b4e10cc8b057df95b3a363785b77b548716742720c3d09363bc60f18b9b' 
  AND token = 'BJgFXIn0W5W+VhLY0EdKtZDYVZ7XsmVolpaOCVVG9Ko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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