SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f0de13db1615a9e5419bf5d6cc3d324126f06e15cbd8e267a5f5edce4f82b66' 
  AND token = '2kwbglWRMSzrNtFxyDWhi/hY8qPa84mH+v5q+GylK+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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