SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '732387bf44510ebc3392a8a6d6d4bec346b2ad67b6a4962f721f2997fcae652e' 
  AND token = 'QmyfNiGAI+DmOHNHprX/0+RPjY4+iOW3jGbbJQeZB74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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