SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce99039b511a9d031738867c6e4a40eba371cbfef2843eaeb41dcec6c760b57b' 
  AND token = 'OazpYAr8o9YJr9YEwAd+Xy8tZN+RosGz8R7i+asBObc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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