SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5836b6801c1b8a488beb554f79b4682d70097414753d610cefd25f7c4f5bef1c' 
  AND token = 'ICZOQGd3u+MF/cJbLLzkq7BPpgM4IM2wonnVIv7MrMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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