SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbcee0cf61bc001e17de252eec401acf44bcfd3743db757ddbbd9b7275063254' 
  AND token = 'yVxghjesXQga+pytqHPrnrhT8CCyclEE1HKtLQEsCec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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