SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6458341754ebdafba01b6d680af4461ed43df25ce79fa5240f0c0e67a5255eb1' 
  AND token = 'yweYjNACwxRDpKtzzCOyZd+xTcTyXwVK6MgPmk4QrFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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