SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f4e87aa2da9cda529884c39861c23ab29cd4627cb3e7aed2c25f9bb60f6d9e2' 
  AND token = 'nYwOkkqLv3u4Ypi5imyv/Vjax0qTbBzOghuWEQqM4y4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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