SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '088a889c48e00cc4c047609a8775eb54c4850dfe5b58f3abbb8326cf3624bb53' 
  AND token = 'YhYV2fjNqaEkBAtU1a8Hmu/GqgvhmTRkQyySpneJhjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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