SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '219794ccc376533938dfec10e212d2f3071e529d90235c7454215ef0b9150669' 
  AND token = 'xGkgJzcpDuVNgu8BR2OirVxFKIWhehu3Y2YSDWY8fGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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