SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ce8d2609d96aae2d0aab562dabd0a36f04174097ce4119a3c5bc9fc90618e49' 
  AND token = 'dcQLB8Lg6SX+Tl3YhJ5mxwtk7WhLoaRjIhRvk6cUIyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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