SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3374fc6e5315f79da7d84f6c06e1d33ad3935d215539aaa2bdfb8edece8687de' 
  AND token = 'aJ5tq3gti/cVvjNoiSQSmswivtuJkgKzIHqKIvOhwWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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