SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9b456367279cdbbf283c852a53376937240bc481dc773a5bae30c7c2ab1d87f' 
  AND token = 'l5APfyf5TVvGThLsUu60XL8kmhTO1sFXx8N/lLmXlLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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