SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3ebdaf29ca3a08c82b4fd90dc782a869a18695f24e874b3a1a4af9e966e1a10' 
  AND token = '9RgNQM4w8sT/xUqWSqzHQqCt5fVHWjirGlRbyFC+oZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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