SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '076ce683f74ac9602b9a4bed763da8b8e65eabe17d9789f75d4809799e039643' 
  AND token = 'IhTzr4zsigACPebGxvl14OK5HPMkQMmvyC9V0y5vjK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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