SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ac613789f8c742ebe95cbf195fe78d19e7bc4a086d07930b9c654d0c6e67dbb' 
  AND token = 'D/5Ifekn8b4C6ubseP8PEYT0pTO0aCbTCW+/UbcPDJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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