SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc9ba80194a6d017fcde37bfc4253541ca4c5651eb7121480f4ee6739cf50774' 
  AND token = 'wBnsBIp4G49SuuWZh1VXo8pctkk0KkQXOVe4ZUD2Rxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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