SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a057bf49fd2e666fd9eb350f12a9eb7d9bb99465830e8d6df95a49455a8ece5' 
  AND token = 'OCHMBdZqBkJubWhzcvwIcYYdxGTeZS5pVdf9Rf8lGII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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