SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fb543bae5a96083f34ac5fe08f6e1fe3310943e129e7c6424d33c81589b6b26' 
  AND token = '7XFF9KzvML2FoqRphFRAfngGlsC6ZRaVIBik6fgwBgc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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