SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43d1a015da1f63770ad7edda746275b043b90cc088c926bdde6d2f93df5dea4e' 
  AND token = 'ZaCYz4ZibKwvLv9vnOQOlxLPL9R4MSJNwnDUzMeq5j8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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