SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56c5040407aea8dbdadbc462e293005ae9c99c8025a671516f636b1243a7e7c0' 
  AND token = 'l6wevB6ZMmesN9Ndwk8r4doCDJKe2jlXhQfBPdwHKFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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