SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa6223da60775baa94c414203f71bb969d8e13e3e6d697a6522a3569f7f5dd08' 
  AND token = '98wuYKJDsDosz/+FUHNCn8OgZG1bx+9qe/793/VADvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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