SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8255663aac7801fcd2439d58988d6409c69495aeee91234e8bbea00e8f1362e0' 
  AND token = 'jxIEblEwX0b6UhdoutCfM5ZVnxabCwNZtCaGdwAppnU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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