SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '542b5a5354ac5b9a24109e0f6a9ad5a325c34f2e75c108b212c54b94359f44da' 
  AND token = '6Y1ffATPhRco/4oouN6sKHmESYtXKkVsoDrZDifF0Rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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