SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '57c8480cddd5d71bee26b96734577ad697cd9a37a2376bf8fd1908db2e335c93' 
  AND token = 'y5dYdXFBqHzpgEdl+u4hZRVHrJJMpYT7nFGn325amI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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