SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '577b46e3a49c00dc12afc1d08137ddc2f41b1e5532a2be52182dc280dc0f5bce' 
  AND token = '4qLn/e9fjsBMwRSVR+vBuIMyFYIdwku5V4JN/PwTYXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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