SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7c7f314f1624489fc6b3bb22de8d7573e7d362e9a5c04db08a5f294c3b5b5a9' 
  AND token = 'e9n/CXYJsdL6ipX1IwB+W/Msvg7SxNXCqvUBr2OzCBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}