SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1e6382aabc3314ebaf424853980635598ab1566c37745020bd335026437cb0d' 
  AND token = 'dzV5ndhEIDM0o8Q/xmCcbiRLQTfNnTKkDAtg7r4SrQc=' 
  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"
    }
  }
}