SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff25b8df449cae9f53bed8e592259a23110460c9eda551e77bb3d76bbdefd096' 
  AND token = 'nxJIJPtlG7F1qSuxOBbjPlRBrUiltbtKZh/av9yLQ0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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