SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f257dd511e259a447009437650cb3590d60c00f580acbb44466b7c30eb0392c' 
  AND token = 'jdg/vmJR/QS1LCeuSWQokTOM6+DTjeViL1ZXxqgWkjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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