SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20ba3f22a0bce1858a0fd89e561f692ae888bc2fddeeae3b9ddbe69df3cad18b' 
  AND token = '9NWykODNK+uFTOgWZgje8XzZmqChGFbVyHYuYI4jZ/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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