SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c2bac9ddf48b643f0136b14c7f97f22ca008bf8a5c0b08474d1215917a630ae0' 
  AND token = 'Dx+qWCXsfbQS7TOPnuKJlMklt4mehHFJEg1Alveoj7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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