SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dcc4a67c021b541c0d37eb3e85955281891f7adeead2b93f38a8cd05c89d2a9' 
  AND token = 'RgnHZUZgUkKY33fNNSrOKKZRADD7TOUYLIcaQ7AsLHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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