SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0caf308ac735b15645501f1f482c1d58355678f81974510ae6198ea64dfc8ee' 
  AND token = 'AKx1qnKxQs7OMz3ljPHTnk3BuGQHwOeUy1JSQpXSGcs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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