SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f7e955544479ecdbdec93fe314158e2d682b6adafdcd7fcabf8bd21c13af879' 
  AND token = 'le8Ay09pp0/RlbSZMUFserGhM5uYJvrWN9qr08arNE0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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