SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1402d7c33a0bf339eb10378eb828f1ccff78583c229746ad516e9dd5609bad4' 
  AND token = 'c7lNn+ZSAZPDCCy/UjIK5cMzS/smEi+WDT/4pBG7XvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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