SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25e42f7b6d0ecc846301101684bc5db537053619b52ff1f826fa407b40093f2d' 
  AND token = 'YtHkBX6UjpZYu4JovzMqyKdU9guF3QrcB8qGl1dbJNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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