SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f81a97c34e869d5ffffc847a250f151c60e903005581f93df9bf45ad4e13aea' 
  AND token = 'SGBOsVOu0kCygZ9Gtkf8dOcueHF76RLa/v8tvI7NUbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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