SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46f7dbe2dbb54891fe9dde53f7904d64c57a612b66536f61727ba768556329cc' 
  AND token = 'KJNGJXc9Cz9iBu8dDWQGu50K6PAWk3dpizoaJK/87jU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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