SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8df24735bce339e51dcff7c193996dbb1b01d80e4584a8c9b96d5284dc901176' 
  AND token = 'imGaPW7dccdA1lAYLcDj2oMUPtyDC76pPRz3jZBJBUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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