SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46a6ba73cf92017568b3696321315501673d3dbb87ecd4fc4a2319bf042c8fe2' 
  AND token = 'miE8a7hGjKnhLIjtJvrS6xp/u9N2zPOqOJGt/gcPl3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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