SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2cfae1ac014ba4c8e355db205f92741f9b33a9790f7dbef287c0dc9df49dd8c' 
  AND token = 'AjXtnzWjxeHeuNOnRkpgQ6+7wuU8aYbTvwJB78xvW3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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