SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4311f0a9810fe9811c05562d35e2d95f1c0f09ebd6ce81cd958c070ccac6300b' 
  AND token = 'U5mDP/9d/52ekf/im5qU6DzYcF1wVAeuxmjVmkfnMUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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