SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3244ef64b106bd17817114024bbf4495c7b722bd76e0503a983d7a160e662bdb' 
  AND token = 'KmKsYNB+DAJxNzPYkUnCsmCINyMBVLkrrBfUsOXWGxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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