SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7068ff80ff6842bd9686b151b64197d81af45228d430ed4b4867e40d8c4a970e' 
  AND token = 'X/r1//MJBX1Bi6aUfTizQPY+pwbDhqv3wFetdVu63yA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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