SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f29cf9191fd5d51b33e2070cf70627c8301ef688a3539f1e4f8868b835adabfc' 
  AND token = 'KI6cGtxE0Zl3quLAB5nTw/wsZjt+cif9rud3sDuz9FQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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