SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cf08b208a3f53d63c077ac24daa8a31cb1f976aeb78bf0319f9d7fe28562002f' 
  AND token = 'x5If66lueC4re38cuNQnxycSjeof8xdZ9pCI54am+1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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