SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '597b767ddabbc5920b063c886f35eec47c09dfd9a45b85658f0c57292d822888' 
  AND token = 'V3PgsQ28g6DQhhVYcvylnhrnMkCjFscbHPM0zyLnnGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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