SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39ce851ad1942d31385dd1e313a6bb67a466e51e1de681696378187ce591d6eb' 
  AND token = 'PfpKq2Q0g8jsOI+okQKpvsB0NUYluyNh4zZ5Ix7Io5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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