SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56d265663c7484d01d3356ef900e7e46d8fe0ad8bb6fb32e58bba9f75097f04c' 
  AND token = 'Vp7OxRuscFMEa6nQqvYRLUwnH04qhENGumr9NJapJHI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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