Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5a2f9df7f1e6653fbdd9df3c2e940076e50a027b6cb1fe444e5f795d7aad723' 
  AND token = 'DMBwlq/gnBkkwvsn/cXyoqH0WYYDbyZ/3/foBxUmhnA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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