SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5f7bd6370d557c66d066bb6950b467215b23d0951480a3dc6bac8d2f34345c6' 
  AND token = '4gfuRfk/CoOMbvWXjStHhRMJfe/KBGlJmA+9bmXf6wA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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