SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8e722c993d3656c4297a2eb6b7d905b68b37dc41707423de87f3eb97eb3b4bc' 
  AND token = 'UXFVc7zhpEKjNOzxWwZLbUZgeyBOTk91wZDznQAUMqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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