SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d7c8127e84fd97e35837049bd102959d7df080f618b28fdb248bcb2faf024b4' 
  AND token = 'LZHz6r8TG3EEnHFpP+kXet9R+gF6MuVDkwmMOHf0Cc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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