SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5673ecdad3b49a4050e7f380bd9b21f3e44bf0fc4537b488aafad20f631d6988' 
  AND token = 'irrt3CGndMdBX1U/TQSqyQgVXKsOTsof8SCGRnX6UxU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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