SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71b18b3d2cb4640952668f10256d3e3b3c2f658d15e1ac08e680639bd9427094' 
  AND token = '8WoDCVIKq3JHpCIATBfaND89hnkxy5Gjy3nLIbQYTzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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