SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cd39fbb445ca6228ac2ff3f2dbda8a9194498367330722e932f7c395e30f6cc' 
  AND token = 'fIxEOgzjIl5/0lQJBcmKuLEu6HTWcBJ1JrLlbB5mVlw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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