SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77985eaeb0adf218c848085ea340047534f37a3db64e81e9beb887ed0bdd19c6' 
  AND token = 'pi1lDmr8vUFBWM8gp+et0UjKFBXrK6MWIo2gOiPwOAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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