SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e28c779b2fbe646049d914737ae90d459b157775b169aeb48c0f0328f0531ed0' 
  AND token = '0AlLP87B1nHGLd9BXUHYD00937Kr/4ceHlFZNhP+dyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}