SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe21fc2d12f8094d12aab1fd0d54a3a261531d25e3f63a9fe8ba65ffb71b1fbe' 
  AND token = 'Q/gAMvV9hWwvGg6WG+zfS6cTD5VPJkQIHhLlvO0nCAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00206

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}