SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76e70e9e4a49f233f24ac7c744a6597423160e1c772e2372544b5177c4afd6ed' 
  AND token = 'yStyBUgKuEZo38wzodps6mwjofSeDuJ9WfUGOBOa0E8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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