SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '56584f839b1f65ea8afe3ba2d65d47c54629275ec5dcda91772ba7ff6a2f8bf0' 
  AND token = 'YOm/RJwKywkn5n3UlaJzuSTkm8jdb87pnfGRvEzvAsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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