SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'daf169fed9abea81e672fdc4fbb6e1d293c46801406f89aa33b90ed7153eb702' 
  AND token = 'p6/ooyBWB4JIJ9+VIf+TotsVnfmDD+eIK349CdQT8c0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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