SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7517da6fbebcf4149f3d58f9fb192a8213d8b4e2a86a8d847874baf8e27a95a4' 
  AND token = 'MiqKD8Q3oiqBKo0Eo5rluzzLoi0Soq19Vmy2CEFjnb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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