SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '404ca92133e0e1c86bc95b092c944b90948a9ef6a10d05b0c904579adb3f4205' 
  AND token = 'E6UWCpnKqYxMBtVtG1ZXa3CTD3qJVwKrrw3iASNDKmk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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