SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6b3c660b7df32fc6c68f253ea499b78fda2cafc6d2345eaacc5d45141654041f' 
  AND token = 'VzMB/CRmKfuNLS3fpsV2G6bJ4SQempRMMzYymbtsT5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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