SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd562a8d1624a6adb9016361700a7987a2d56152cf1449ede9777c7059891091f' 
  AND token = '4EKkjK2LMwspXNsa1DYDccMEPTlByPQcOJsN6orCdGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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