SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31458f4886eb21de9b12688a6592121ae9c5f5079238bfc066808ab39d55dc2a' 
  AND token = 'vbgkh+Pjok9CJia7OyRtDoB+mkBbEXWEqkpiiAG/Zg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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