SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9be0f69406aaf6da3556739f381319b5bffdcb04b7552b284e3a5bc6629a12bf' 
  AND token = 'W0crXPjOiIQQWJCAo2Wf9nW6FG6DuPZo+DpzuflO+uw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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