SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f766d5ffd481535d38ac831253072c0475bcab2428d7f0a395bc836172e003c' 
  AND token = 'ZAI570CqC93GOYGA78SsxD8V0vSIdhp/ACPbDVGVuPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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