SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a4e3db883ba3f0694d7bdd0cbe5bf62eb486f42c11a18144d6510dd21645dcc' 
  AND token = 'mpSO6HnZA2LdrMyG5j0t/XYtDei6/jIjnWsWuhsPkjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}