SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e743aaf0e48c7692425d7956313040804b1c9d21c82b093dccb48ab47de86f5' 
  AND token = '7gBOCHveKRUei9Vcyi6hmuyJVpacWa+itF6WJQ+lqn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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