SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae13c171d764802a1abc381a072ae3465d88735410395bbb4de4d51a30384ade' 
  AND token = '9/BMpD56cjjXljWVS3aRrPdoGoqKXRVbmbmRahxsIJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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