SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aece9bbe1538387cc3834072b8e15cf613e6675b2def0bff45b92adf6a3c5edb' 
  AND token = 'nq7SJlu+Epj2lgq8ZCsVixzoQjv9Q4K5JJKH36yBgT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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