SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37e9b7762b4555186c1c2e1e3d39b8671986fa606337f771740effe51da2b2ca' 
  AND token = 'hj7lFaU5hZ58LacEcN7AZTZ0Q+XOeSsitNghCjHPFoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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