SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '136a53c2448fa4480bc91babf3c324d9c6be1682629196f52f6ba55d79e73af1' 
  AND token = 'QUVpvxSjPvOv1UwKZVr4AfWwDHNBqhm/k5DhtNqbHYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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