SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cdec0c37ccb642ef204ef68f46241d6e6186b0f19c9b458ee7a023327016c9c' 
  AND token = 'aODqBHprKi6JbqBT+mbG5uLgz5pvA9VQTSfj+AAUhjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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