SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9846a0f8f346f38dc710819443d77a106f93eb3c58259b11f18a3bb95eea26d' 
  AND token = '4EEGVQzPbzfwZDBHeBlSyCYqbgvcEhieb/ocW9IuxUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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