SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2b100714a7d8968f6fefeb561555963f5e5c904c8bd30fb4b50858322287d3b' 
  AND token = 'hAjdY5GfQavZNqMFtMSQylFBmTkXcGPQ1FV597GA7MQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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