SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '328fd4722343586286ec5addf6eb541474f625698fddabde89280ebc1c450f4a' 
  AND token = 'IJptCXtA5XVjb3/UdKr2jQIBh9wMk6DKlgTiVESn/80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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