SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a810fd2049ceaedc98a31907a8b6fe35baa17003a76dd3e13ded7d981f19eac4' 
  AND token = 'HzUfC21VnFyw/llhtVIeuni5WkRL7zhvTTOUTZw/xpE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}