SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8369ded77f5abc919e3f81b790ba4f7e7f86ed2119c4b133735eba828e40d9f9' 
  AND token = 'IgGEUGMwOIxBINJf4wqz+XIsqrZpkkDQ0f0C7eJYxK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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