SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd8b4b5203f74f24c9527bb182798237680da0e1603e1c8138a65ab7106f2798' 
  AND token = 'GmlyBMX28WPef5TRynvDbH8EomPKh+Yt2n9XktCJfxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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