SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '592eafc7cf0c57c744f6632ccde2942227a55d191b7fc4e4f93a51a101aca1ce' 
  AND token = 'JPRrjWtzGVOlp+vu2hnJpWY9NyHRTEFQJVGwKSoRg3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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