SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1589c9b7a98481893f2dfdf99b583b5ce173cf46575dc6078364cf3cb68b1eb2' 
  AND token = 'O1Zuc3uPuvLkeOdreFfM3pb604XjSdaWRSJBQVBbhDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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