SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '451f14a67b0cf908d4f8fd3051e99dbb42ed993357b971ef39b2cf326c21e7de' 
  AND token = 'kgCUuwPQYrFiJ/L+HfLKwERVVdQHymqJy58dyPtPZO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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