SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a34ba58e66c5c5ebb6295c8449ebd02974137b741d3c940319008bfed3cbf43' 
  AND token = 'QZyI9QT7NYxFaQ9hYK33YSsq0n6AjjicgybTbl29XfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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