SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '583baac8b85d5d4c453b1d38627070885c582d501c388efcf8e7b400474dbc90' 
  AND token = 'w9Wqy9RhJ7QPkWBLrH1FYeUyAGkXNw5ZnGXQD5id86k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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