SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d207efe6ac6d69251102fec77532969b5bad42bcd7dbf8cc6e545a6e3992034' 
  AND token = 'u9JsflzDif96eGucU9bo5DhPwGjBXVu8jbA8IKsFF2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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