SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f91b94d49046e2c35362476cd56809341cb1a4d83a97c65cf9c536e23ee86473' 
  AND token = 'gMy3FuRFuKJkDUW0nsH0krQg5FTlJUXd/UeKDb+hsPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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