SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b5d3b4affd25ac20545bc06b6e2bec0d436f294438495b10346a387efee8219' 
  AND token = '7FJwQ/F9OtkI7IatEPuiilk1CxRMuxjEwcTX6T0sboQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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