SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d84c539ae686ffe38c88fc0da0d1980a36a7b6506bc48f720309a22632a52b6' 
  AND token = 's++2P4GLw980Cneveqs1JieCnrAcBGPaZVlzyQfW/qY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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