SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72893009b3fa808c2527e9ceaa906b8829a5923dbbd14778193847a6424df721' 
  AND token = 'PEdex9oIxIGQO7iYUkau7EEvaZLPDJJ333DjUP1yYCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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