SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fcddd3170e557962311d68d79df14f1fe84494a9b4307eeb26975c5a2217263' 
  AND token = 'gbgZdAdCME4Jmxk95V73eG3YSvORuCWwmPncTGJXS4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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