SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd2fd720d7d11a5b715ec9eae6018488a2ef77dd6bbd6e321ca45390ccdb5e23f' 
  AND token = 'dMX4/Gc66bd7FOvCMKmTZVuQ3jhG4tZUnhGo9g/PDzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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