SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e71cae135afc7dceaec3cd6f7fc5a5cc5613f795005685d71adef455cba41a0' 
  AND token = 'WeHqLc9IBf1ZnFAnT9Ee4yJ+hRC/IQOcwA7mM/+YvhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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