SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28aadb02b5d17bb0480815ce6a1f77e9aca8dfff6f738d85aede2e98043530ea' 
  AND token = 'CDhiTdY6QY87CCT18xl4EchLUf67KVrtFLkd5uZsx40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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