SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b3ea45ed55928c8de02928417246df7c16e32d3f2472325887fea3f0fd8fe61' 
  AND token = 'ZxtBZU0S16RGzxRR2EDWGKoscHxbhb94nBpNmCsQVXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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