SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd42a001398596c7eaca3d9da75ddeacc72de08dee788be048c7040c822cfc944' 
  AND token = '1gS8yNajVf1QzWTRPBq4/Ci+u9DV2dxDHlJv87A9ZQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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