SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '291055495ba939f5b331e24a6eb9c95f2db2b9607ca08418ebff5f7bba499fbf' 
  AND token = 'bEctQhhM8SgaXz45kLQ/PSrskdGoy4TekSzYzgAtLOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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