SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3276f0aab84b5f6bc16961017a9b171dcc1fd4022fb709fa7259ec62b1ed8339' 
  AND token = 'vQ0JUSUNds/njws8K8FRHW6tcDqxZPq7DjphNBp+bUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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