SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c99e8e0f254b89d79490ee49cbdf1abef9d77b45d382a3ec92a6626575537073' 
  AND token = 'tw72k4LLXWLxLu/TkOanBZxntFP2mEoezg3+jSIz8No=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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