SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8a724ff449b72202917ef7b8dcf36c171e3c26a2112acc69984df5532855505' 
  AND token = 'hfSNjoNmePzox+oFiK5vINSnZVKd/ESJDjhHBx2Y9gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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