SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b1df1f8809b531793296c38caa46ada625606d96b05a9ac70594d9c01a276a4' 
  AND token = '6z8CTZH7JsJzJmGZmthxX5Ks3Yxp2z29DzWSEOx2I6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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