SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c50931e79f3e0ce3d108536bff99fb75bfbf53398a98c0bfd612f26c09a4ec93' 
  AND token = 'CprYiZN2CXIU9H4f9dGvgeGjhGCV943PVE7I+PkiGIU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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