SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1398e2cc7cbd54ff1288285f325358b3b4e3e89a94503a23634680f94b0fe9f1' 
  AND token = 'G9XOl2JeqEE/jLFGnxzdcdld2hez/tbXOAsB3Xhga1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}