SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f048be155dbeece11175a29d9f5aa6673287bf0896b2719670f105226d5f6c90' 
  AND token = '1RSILJAt8kbiHv1j0ytzLKw6nVhgwk+ygK+5u0M5vqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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