SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9868ec792f48ff81dec19ec014aae021cfd5281cc9b167ebfc69b8faa2f9956c' 
  AND token = '9RsxQCsLrxwINLpNmvPnkw+7jY/2cDUngRXlhdfBgLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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