SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '990d4a6e4ed59d8c8fe767f3cb7bb0df8aaedf1f9c82b64843908568eafc3833' 
  AND token = 'YToPZpVs+BTpENGr8atQC+ylxUIJkfigSqtn+hY+VVE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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