select values in json into other json (Postgres), PostgreSQL

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--PostgreSQL 9.5
--'\\' is a delimiter

with t(value) as (
  values (text $json$
{
  "eventSummaryList": [
    {
      "customer": "189256",
      "data": "{\"cliente\":\"189256\",\"data_posicao\":\"1491426372\",\"gps_valido\":\"1\",\"horimetro\":\"120561\",\"ibuttonHex\":\"0\",\"ibuttonPart1\":\"0\",\"ibuttonPart2\":\"0\",\"id_evento\":\"null\",\"id_motorista\":\"0\",\"ignicao\":\"1\",\"latitude\":\"-2222222\",\"longitude\":\"-2222222\",\"odometro\":\"253692\",\"pos_memoria\":\"0\",\"veiculo\":\"44444\",\"velocidade\":\"50\"}",
      "identifierEventRule": "77404",
      "identifierRule": "6",
      "identifierSummary": "28901976",
      "rule": "velocidade_maior_que",
      "status": 1,
      "vehicle": "44444"
    }
  ],
  "header": {
    "mensagem": {
      "estilo": "SUCCESS",
      "mensagem": "Successfully executed service",
      "plataforma": "EVENT_POINT",
      "status": "SUCESSO"
    }
  }
}
          $json$)
)
select ((value::json #>> '{eventSummaryList,0,data}')::json ->> 'velocidade')::int
from   t;


absolute service time: 0,83 sec