SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac26ff22ccbc45f9c6391cb0956152c72bc3551313f0c5bf7c3796e8903da96a' 
  AND token = 'LXgdUwO8GFXDIX7UYU1BVS7AO/wh0WgepHO2OdJ4xAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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