SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dce210718aca4ace8bae684540c34e2d41f3af840174d0f683c1d8b71aa4d9ed' 
  AND token = 'HhTnlNUlkmyPgf54Jr/mJPansNKDfP5DUo+umGLYKFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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