SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d295ee3c16113f70d0d21ef23da403999a0bf1ae3c0224b03d417f1e43a687c' 
  AND token = 'MvmahHrJbHdjLxkgeVaoqspaLMUY8SEGkgwpSW1OL+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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