SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9367b10731b6fd851877185c6930be9e797bce9e18a5307cc1afa3c15e39c4d2' 
  AND token = 'ka/sWrfThd8Ey+4aj+2gZwtPMxuCQ+5UQJaJkfY0RIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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