SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '856feca985a508b426b214e740e8ab6b9414d06b3a51b7d7076d8da7151af44e' 
  AND token = 'hLFosO/GxNkJvVwEW5MHAyLSeQOMVLadcRSWCN0bB0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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