SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cd36ebb6a85753798350b91830724faac2ed82db4a25015e043cffa4ac98673' 
  AND token = 'xY8Q8OA1Q3xgV8lDmOvlBhHoZUQI6+FcPFJwT8lfzGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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