SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3879f8bac453f10973cc33d102c8cb1817a02c9365d12d3ecff2f72eeb74587a' 
  AND token = 'IBKMkLRUj0GHNf9R5L1/MUQXVL5Qm3EkYLV3moZ7qWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}