SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c5585bef37f1b09b12ea934a29678419af3c9478008a8f55d28bd9771e74acb' 
  AND token = 'HMirPzEY/kvqJiPuiClanbV5YIgM+QOYZgl46VktjyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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