SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4bf8ed7c93cb7fd600f8086e7fc270838f03b218ec6e29c02ea2102042b041d' 
  AND token = 'BdNB9Wo1qLcae2klqWgtEAnWnFbjs1TpIkEI3wJPOGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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