SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2de8c4606f19d608c44b16441fb7fc276bb346df4f341d4afae462c1a1d63fa7' 
  AND token = 'NBhUw10NyzUpeliCf47wdai4KcwDrvz5/BeNWssSdk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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