SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c962c31f66dc438927fd94c15bed8976576890c6e0abf381ac14de0f3537603' 
  AND token = 'B2++87ZgqfqNdgBqKkm9pxUyXs9DCaNymFvYUGWoEd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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