SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd764d2e569ef56c5d1ea709e1530050ddb9218bb9ddbbf9af467b11e9688919d' 
  AND token = '2G+YAfxVjRBtiQqyzoWgxrnCyDe+A/vHEw378EhaBiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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