SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6323912faef0728306f8ab8eb510a53faec214be8f7f2b83e82ad7ede83dc354' 
  AND token = 'XIwBo8CJ6C0MuLjYbkjiFHvMTyN371lZCI1M2Lkvnqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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