SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8153f7ae968a5f71d6a6ce34015582cb94820139d6211f965125dedbec4248a9' 
  AND token = 'MKJjY8yGL6ApWbRj1nnVTMnIW+W2A8VruJUjQpApCPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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