SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '409ef9f0ad876fda7a4c12d15e1000f3af3d8d57f3dd3c384f707914b1fd9f11' 
  AND token = 'tvggdAOCfIZtLKH1quXiv0jX+KD31941RbM3bGni3OU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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