SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfd3b94b442109e4beaaa22b44ab4cd691dbd3c5eae20f17249f69120e221045' 
  AND token = 'FkHmDfOsvJRKTKJ+DyxoI44pFYdwIJhpWQ8OA8VvHMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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