SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eeec77c2cbd3346255e109dd2bf99d09d254bdbcb186bdf82d75002daca90b8d' 
  AND token = 'KUtFt5eyZorKVIHQMVOVROk9McVNLe/iVg7VC2LjMj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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