SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b61eb1480644b479b34eeab08b3d8d05b764fe62682dbfe8feb7f037dd9d6aa' 
  AND token = 'gjFxKskanz1yPOlMnK7ASACr7UP5JXaPK6GQvyU807M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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