SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b3ff8521e2c4b8c3d267c625a26b43e93d589ef911d25c0a70577f0a2610857' 
  AND token = 'VuQDowIqolKl/6yr7gwZ10JoWlVtzkP7in4VcSxijZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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