SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '682799424bd7dafd2e8e19c637a7302ca0134c42cdc9aa52d3f7f4a6a49e3caf' 
  AND token = '/VfsUL2RxBEY6hW+03fbR5+GQHY5BefMhwphAHyuYWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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