SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afebe362bab7af6c9333981b24dd6f5423648e95cbf0462cf70c71b954bef2e8' 
  AND token = '9xj/iqLW/PlPJfMhT/1Hdq2dxYjvS4iYVwyVHBzO3hs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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