SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adb92ec741cd2c257a8b4fce88bc5bf1008476d364e995a048b3a74607631223' 
  AND token = 'KBqMU0CDUFTeXgU1XIfc3Yp+jf7LepUg7l4z9iOqGKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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