SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2e71b92a4c4e793f475cea041f6e40b1394a0c444a22b72409bde97758f53b49' 
  AND token = '2EF3/mIQeSTIhSGTcVkhXHq/NYauCvBqr5K0qboHjvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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