SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a668e434f4142ffd804b54840dad0da6631198abb0bae6a9f2578093ebe0afaf' 
  AND token = 'cbbn2XWVED6Rl9wEFx1qQZ8FBWLxNOeK2ZEE7/2sD6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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