SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40d984625561267c0df01a04a38cc4802a4c59186f1945566aeb1cd577fcdcea' 
  AND token = '2B6Mt3wdcLr+4PCRQfeyus5NPNYyDBGW1LFPua9/hv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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