SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a23d78753f39cf6aabb9e066fc0c79629beb4fc7afeb9dbc27057fa0a151bb3' 
  AND token = 'rHIXyYjvcA9jOYAlfoU53UpsDLElKvTgCkZKtyR9C8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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