SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03258fc6038d915576cf6fd33bd02cd726066dae7eda8695624a4fcf20817ebc' 
  AND token = 'tblFajnQuDqln1RPg1OMhf7B48kxOcGonDjYihAItcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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