SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa8c2a928449f607d7801c1a05ab521c757feb46703689d429a5224c9319160d' 
  AND token = 'RU08fgYTFUm9kaubQUkxEJkFwidbkZmGm11572x23xc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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