SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e597f23e18579eba1ad028e8c880cbb81f66e73f3ff9d9f0a95fe700680d7b7c' 
  AND token = 'B9mZDHVItBCD5zpbWBgDguK+KLEmjqodxt1bNG/RRY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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