SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '533dda3492953fc08398580665b0c56023c88819285776c44e4d6a4cbbad65d2' 
  AND token = '1XHUGfMRoUwcwAtj78Dcxd8gTafwU+K8FYp6uW7BI2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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