SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e646c853c441b5830a10188a51cb1394a687a289dc17e5797750b1d20bd9144e' 
  AND token = 'pfnTRADwloxI8L2o+c8gQcG8nOQFV3xTCHttv+aEX2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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