SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c83c25011cceb54b7c156fbb65d7b76891b27e554b29ec1d2b390174583dfeca' 
  AND token = 'ZdQT3CQAp3Rtc9DgL3sfUT5v8L7asWSItqMiv7MNERM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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