SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c35a02b13f78b2b7da75f7b5f6061dd797761a2785777c23500b0c1274d33998' 
  AND token = 'qG4CgAMwO1sxzYIvOz8/oVxskgGgnllsjcKjUhbxZbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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