SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef656cddb1d11329e0857c7ea24bf9b56d37aed464b7b64c1e0a44f81306af10' 
  AND token = 'lfmkQGOqFIbZpKftFFtA/5ZOV8UdnvnJRCixFgaw7os=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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