SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38917cb4665e8595eac72a977d8eda649d556a9c75a17a020e78ea296a184036' 
  AND token = 'W9azxcDogPlmGBVJbwQN//+tCq+O/UbYh42oT5Bsx0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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