SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da4945d5f4f7c3a16926716b8b7164ee5dc992ec0e7f7eeb8ee2c7545b2e653f' 
  AND token = '3QpU9/z8fkQAjnv7TmByvRCluL+v+hZkUyvwwxI0ruk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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