SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffa1ceb175bf61ebf5f157ad621dee04f0910ea8f3a6a2d2f027f24ec65c6968' 
  AND token = 'ROevnpL3g9BefFmXiaiXi7WnGCFM3Owcn5TLnWejpfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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