SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fa2ad72e8d9439a2c854763c9897c99773008519bb4537c6c51e3ffb7f7a691' 
  AND token = 'uKhx1LsXdGfHe/29Yud6zUjSXazBoIXukPa2FeZoNwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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