SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16982da1641b4a353276bf96a821af40cb1f99fd26aa5eb13efd6358788c2d52' 
  AND token = 'gxAY0JyOnin740ZDPeL/puwDDdEVJSGz28VmVvO7Gj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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