SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f9e74f9f53aad4cf90d95d0edfec191b9d761fc3a57af942aa6df1741b3dcbb' 
  AND token = 'zqtTRw+Y2IWwtTnOAvli+7fYxXJCPDcSVwXaEppbv+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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