SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bc384c90615a785650527b553c0a7e1a9978319679ad2579b6689108993558f' 
  AND token = 'TNvYw3mnZJViBPHYlbd2gQVoliBd4A8Y0WdOHFnX/EI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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