SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67e0dbf573832a173bc7728d272bbe8373412703c7c4b9689d45aeacc31ee00a' 
  AND token = 'K6uFyD/9fvZZQWWzY4xxg4kLR7TyU9V6hHPK8JlulvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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